The use of medication during pregnancy is directly related to the physical and mental health of the next generation. The physiological and pharmacological peculiarities of women during pregnancy, as well as the sensitivity of the fetus to drugs throughout pregnancy, make the safety of medication use during pregnancy a focus of attention. Pregnancy is a special stage, and the use of drugs for pregnant women should be considered from both the mother and the baby, weighing the pros and cons to prevent inappropriate use of drugs and ensure the safety of mother and baby.
I. Pregnancy drug incidents in the last century (hexestrol, thalidomide)
With the continuous improvement of medical and social conditions, the issue of perinatal medication has become a growing concern. In the past, the main consideration of drug use during pregnancy was the treatment of maternal diseases, but less consideration was given to the effects of drugs on the fetus and infant. in the early 1960s, the painful lesson of the “reaction stop incident” that shocked the world and led to thousands of fetuses with short limb deformities aroused the high alert of human beings to the teratogenic effects of drugs and the high concern of perinatal drug use.
1. Hexestrol and vaginal cancer in adolescent girls
Between 1966 and 1969, doctors at the Boston Gynecological Hospital in the United States discovered eight teenage girls with vaginal cancer in a relatively short period of time, exceeding the natural incidence of the disease in the teenage population. After intensive epidemiological investigation, it was demonstrated that these cases were causally related to the use of hexestrol during pregnancy by the mothers of the patients, with a relative risk greater than 132 times. Other hospitals have reported one after another, and by 1972, 91 cases of vaginal cancer between the ages of 8 and 25 years had been reported in various locations, of which 49 patients’ mothers had taken hexestrol during pregnancy.
2.Thalidomide and seal limb deformity
Thalidomide (Response Stop) was first marketed in West Germany in 1956. In October 1961, three German doctors reported some cases of children with seal limb deformities at a meeting of gynecologists in West Germany, which attracted attention. Later reports followed elsewhere that many newborn infants had unusually short upper and lower limbs, or even no arms and legs, with hands and feet directly attached to the body. After a long epidemiological investigation, it was proved that this “seal limb deformity” was related to the use of thalidomide by the mothers of the patients during pregnancy. The investigation found that the drug caused more than 10,000 deformities in several countries, with 6,000 to 8,000 cases in West Germany alone. The United States, Switzerland, and then East Germany were largely spared the impact of this event due to strict controls on the approval of imported drugs.
Second, the factors affecting the safety of drug use in pregnancy
Pregnancy is a special period, the mother and fetus are two independent individuals in the same environment, the mother’s physiological response and sensitivity to drugs is very different than usual, the fetus mainly relies on the placenta to obtain the necessary nutrients and excretion of metabolites, the use of drugs during pregnancy, due to the fetus to the mother’s dependence on this relationship, is bound to bring about the impact on the growth and development of the fetus.
1, the pharmacokinetic characteristics of pregnant women.
Gastric acid secretion is reduced during pregnancy, gastric emptying time is prolonged, intestinal peristalsis is weakened and slowed, the peak absorption of oral drugs is often low, and the oral effect is worse in pregnant women with early pregnancy reaction; blood volume is significantly expanded during pregnancy, plasma flow is increased by 35%, blood dilution, blood drug concentration is reduced, renal blood flow is increased during pregnancy, glomerular filtration rate is increased by about 50%, renal excretion process may be accelerated, which may also lead to lower blood drug concentration. The half-life of drugs may be shortened, so the dosage and dosing interval during pregnancy are larger and shorter than those during non-pregnancy; plasma albumin decreases during pregnancy, the protein binding rate of drugs decreases, the free drug in the blood increases, which may lead to an increase in the volume of drug distribution, the burden on the liver increases during pregnancy, the clearance of drugs by the liver slows down, the renal blood flow decreases in the supine position during late pregnancy, which may delay the renal excretion of drugs, especially in those with hypertension, the renal function is affected and the excretion of drugs is slowed down. The renal blood flow is reduced in the supine position in late pregnancy, which may delay the renal excretion of drugs. These characteristics may lead to accumulation of drugs in the body.
2. Pharmacokinetic characteristics of the fetus.
Most drugs can enter the fetus through the placenta, and drugs with high lipid solubility, low dissociation and low protein binding rate are more easily transported into the fetus through the placenta, and drugs can also be absorbed in small amounts from the stomach and intestines through the fetus swallowing amniotic fluid. The drugs are mainly distributed in the fetal liver, brain, heart and other organs. Due to the imperfect development of fetal liver, the lack of drug metabolizing enzymes and the low detoxification ability of drugs, the low glomerular filtration rate of fetus, the delayed excretion of drugs and degradation products. On the one hand, the transfer of drugs to the fetus through the placenta is often much slower than the transfer of their metabolites to the mother for re-metabolism, so the drugs tend to accumulate in the fetus. On the other hand, the blood circulation characteristics of the fetus cause uneven distribution of drugs, i.e., drugs tend to accumulate in organs with more blood, such as the liver, while in organs with less blood, such as lung infection, it is difficult to reach the local effect, while the unbalanced distribution easily leads to drug toxicity.
3. Developmental characteristics of the fetus.
Within 2 weeks after fertilization, after the gestational egg is laid, drugs have “full” or “no” effect on the embryo.
”All”: Harmful drugs destroy all or part of the embryonic cells, resulting in early death of the embryo and miscarriage.
”The embryo can continue to develop without any abnormality. 3-8 weeks after fertilization, day 15-25, the central nervous system is in the stage of differentiation and development; day 20-30, the bones and muscles of the head and spine and the emergence of limb buds; day 20-24, the embryo is in the stage of differentiation and development. Day 20-24 is the stage of embryonic organ differentiation and development, cells begin to develop directionally, it is difficult to repair damaged cells through differentiation and compensation, when affected by harmful drugs, it can produce morphological abnormalities and form malformations, it is the sensitive period of drugs, especially during 8 weeks is the highly differentiated period, it is also the highly sensitive period of drugs, the greatest risk of teratogenesis; 9 weeks to full term is the stage of fetal growth, organ development and functional perfection From 9 weeks to full term is the stage of fetal growth, organ development and functional perfection, only the nervous system, reproductive system and teeth continue to differentiate, especially the differentiation, development and growth of the nervous system reach their peak in late pregnancy and neonatal period, after being exposed to harmful drugs, due to poor liver enzyme binding function and high blood-brain permeability, resulting in fetal functional retardation (IUGR), low birth weight, abnormal functional behavior and increased preterm birth rate. There are almost no absolutely safe drugs in pregnancy, for this reason, unnecessary drugs should be avoided as much as possible.
4. Pregnancy staging (safe, hypersensitive, intermediate, hyposensitive)
Generally speaking, the time of taking the drug occurs within 3 weeks of pregnancy (3 weeks of menopause), which is called the safe stage. Since the number of blastocyst cells is small at this time, once affected by harmful substances, cell damage is difficult to repair and will inevitably cause spontaneous abortion. There is no need to worry about having a deformed baby when taking the pill at this time. If there is no sign of miscarriage, it generally means that the medication has not affected the embryo and the pregnancy can continue.
The period from 3 weeks to 8 weeks of pregnancy is called the hypersensitivity period. At this time, the embryo is most sensitive to the effects of drugs, and teratogenic drugs can produce teratogenic effects, but do not necessarily cause spontaneous abortion. If there is vaginal bleeding related to this, it is not advisable to keep the fetus blindly and should consider interruption of pregnancy.
The period from 8 weeks to 4-5 months of pregnancy is called the medium-sensitive period, which is the period of further development and maturation of fetal organs and is more sensitive to the toxic side effects of drugs, but most of them do not cause spontaneous abortion and the degree of teratogenicity is difficult to predict. The decision to interrupt pregnancy at this time should be based on a comprehensive consideration of the toxic side effects of drugs and other factors, weighing the pros and cons before making a decision. If the pregnancy continues, amniotic fluid and ultrasound should be performed in the middle and late stages of pregnancy, and if fetal abnormalities are found, abortion should be induced; if chromosomal abnormalities or congenital metabolic abnormalities are found, depending on the severity of the disease and its prognosis, the pregnancy should be terminated early or treated in utero.
Above 5 months of pregnancy is called hypoallergenic period. At this time, the fetal organs have basically developed and the sensitivity to drugs is low, so obvious malformations do not often occur after the use of drugs, but developmental abnormalities or limited damage may occur in varying degrees, such as fetal growth retardation caused by Mildron, brain damage caused by phenobarbital, deafness caused by streptomycin and quinidine. It is important to be very cautious when taking drugs at this time.
Pregnancy drug risk level
During pregnancy, the fetus is connected to the mother’s body through the placenta. The mother delivers the nutrients contained in her blood to the fetus through the placenta for its growth and development. The fetus passes its metabolites to the mother through the placenta, and the mother excretes them on its behalf. When a pregnant woman takes a drug, the drug enters the bloodstream and also enters the fetus through the placenta. Therefore, it may cause adverse effects on the growth and development of the fetus.
In 1979, the U.S. Food and Drug Administration (FDA) classified drugs into five categories for their possible effects on the fetus, and this classification is now widely accepted and used worldwide.
1, the concept of drug risk class classification
Class A: Controlled studies have not found any risk to the human fetus during pregnancy, and such drugs may have little effect on the fetus.
Class B:Animal studies have not found a risk to the animal fetus, but there is no control group for human studies; or have been shown to have adverse effects in animal reproduction studies, but have not been proven to have adverse effects in very good human control studies.
Category C:Animal studies have shown adverse effects on the fetus, but there are no controlled studies in humans; or there is no information from human and animal studies. This class should be used only if the potential benefit to the fetus outweighs the potential risk.
Class D: There is definite evidence of risk to the human fetus, but these risks are acceptable for the benefit of the pregnant woman, for example, when the drug is life-threatening, or when the condition is severe and only safe drugs are ineffective.
Class X: Studies in either animals or humans have demonstrated fetal abnormalities, or human-based experience indicates a risk to the fetus, or both, and the potential risk clearly outweighs the therapeutic benefit. This class of drugs is contraindicated in pregnant women or women who may be pregnant.
2. The safety of drugs commonly used in clinical practice is summarized as follows
Class A:Fetal safety. There are very few drugs in this class, vitamins belong to this category, such as appropriate doses of vitamin B, vitamin C, etc.. However, the amount of vitamin A in the normal range is a class A drug, while a large dose of vitamin A, a daily dose of 20,000 IU, can be teratogenic, and become a class X drug.
Class B:Relatively safe. This class of drugs is also not much, some of the commonly used antibiotics are in this category, such as all the penicillin family and most of the cephalosporins are class B drugs. Lincomycin, clindamycin, erythromycin, and furantoin are also class B drugs. Although metronidazole is teratogenic to rodents in animal experiments, in humans, a large amount of clinical data accumulated over a long period of time has confirmed that early pregnancy application has not increased the rate of fetal teratogenicity, so the FDA has placed it in category B. The anti-tuberculosis drug ethambutol is a class B drug. Among the antipyretic and analgesic drugs, indomethacin (anti-inflammatory pain), diclofenac, and ibuprofen are all class B drugs. It should be noted that taking indomethacin after 32 weeks of gestation may narrow the fetal artery duct or atresia, resulting in fetal death, so indomethacin should not be taken after 32 weeks. Among the cardiovascular system drugs, digitalis, digoxin and cetiran are all class B drugs. The adrenocorticotropic hormone drug prednisolone is also a class B drug.
Class C:Use with caution after weighing. There are more drugs in this class, which are either not introduced long enough or less used in pregnant women, mainly because there are no reports on whether the early pregnancy application will cause damage to the embryo and fetus, so it is difficult to have a more definite conclusion. Use caution, try to use alternative drugs, and when necessary, weigh the pros and cons and explain to the patient or family the reasons for choosing the drug. Most of the antiviral drugs belong to class C, such as acyclovir and zidovudine for AIDS. Some of the antiepileptic drugs and sedatives such as ethosuximide, barbiturate, pentobarbital, etc. Among the autonomic nervous system drugs, cholinomimetics and anticholinergics belong to class C; some of the adrenaline-mimetic drugs belong to class C, such as epinephrine, ephedrine, dopamine, etc. Among the antihypertensives, methyldopa, prazosin and all commonly used vasodilators belong to class C. Among the diuretics, furosemide (tachyphylaxis) and mannitol are class C drugs. Among the adrenocorticosteroids, betamethasone and dexamethasone are Class C drugs.
Class D:Use as a last resort. Because of the available experimental and clinical evidence, drugs classified as Class D are not used during pregnancy, especially in the early stages of pregnancy, when possible. Typically, such as the tetracycline family, tetracycline or hyoscine are used during pregnancy, destroying fetal tooth enamel and causing yellowing of teeth in adulthood. Aminoglycosides are not used during pregnancy, such as streptomycin, which may damage the VIII brain nerve and cause hearing loss. Antineoplastic drugs are almost all class D drugs. Analgesics are class B drugs when used in small doses, and class D drugs when used in large doses, especially when applied for a long time, mainly due to poor fetal growth and development and addiction to drugs after delivery. Among the antipyretic and analgesic drugs, aspirin, bisalicylic acid and salicylic acid are Class C drugs when used in small doses, but become Class D drugs when taken in large doses for a long time. Antiepileptic drugs are almost always class D drugs, and their use is directly associated with adverse fetal outcomes, and the risk increases with the number of drugs used. The most frequently reported malformations are orofacial clefts, cardiac malformations, neural tube defects, and developmental delays. It is important to note that the rate of fetal malformations is higher in patients with epilepsy than in the general population, and the use of antiepileptic drugs increases the rate of malformations, especially when several antiepileptic drugs are used concurrently in uncontrollable seizures, which is something that must be clearly explained to patients and families when treating a combined epileptic pregnancy. Among the sedative and hypnotic drugs diazepam, clorazepam and doxazepam are all class D drugs. Among diuretics, hydrochlorothiazide and benserazide are class D drugs. Coumarin derivatives (dicoumarin, ethyl dicoumarin, warfarin) are class D drugs, which have low molecular weights and can easily pass through the placenta, causing significant malformations and fetal defects. Miscarriage, intrauterine fetal death, and neonatal abnormalities occur in about 1/6 of warfarin-exposed pregnancies. The fetus is at risk for warfarin syndrome (FWS) when exposed to warfarin in early pregnancy, and the most dangerous period of exposure to these drugs is the 6-9 weeks of gestation, when the incidence of FWS can be as high as 25%. In mid- and late pregnancy, fetal exposure to warfarin causes fetal central nervous system defects, generally due to early fetal hemorrhage and secondary scarring, followed by deformities causing abnormal brain tissue growth and development, which are rare but more clinically significant for the infant than FWS. If the mother requires anticoagulation, the use of heparin from 6 weeks to the end of 12 weeks of gestation, followed by a switch to warfarin and again after full term, may reduce adverse fetal outcomes.
In fact, there are thousands of drugs available for people to use, and there are Class B, C and D drugs in each class, and Class B or C drugs should be chosen over Class D drugs whenever possible.
Class X: Absolutely prohibited. There are not many of these drugs in common use, but they are prohibited during pregnancy because of their high teratogenic rate, or because they are very harmful to the fetus. Known teratogenic drugs are: angiotensin-converting enzyme inhibitors (ACEI) class, alcohol, androgens, Maryland (white elimination), carbamazepine, chlorobiphenyl, cyclophosphamide, danazol, ethylene estradiol, retinoids, isotretinoin, lithium preparations, methimazole, methotrexate, penicillamine, phenytoin sodium, radioactive iodine, tetracycline, sodium valproate, trimethoprim, etc.
Chinese and botanical drugs: It is difficult to estimate the risk or safety of these drugs, usually the composition and dosage are not known, and no human or animal studies have been reported on their teratogenic potential, and knowledge of their complications is limited to acute toxic reactions. Since the safety of such drugs for the developing fetus cannot be assessed, pregnant women should be advised to avoid such drugs as much as possible.
IV. Medications for common complications of pregnancy and commonly used drugs (hypertension, diabetes, colds, vitamins)
1. Hypertension
Hypertensive disorders in pregnancy are a group of hypertensive disorders seen during pregnancy, including.
(1) gestational hypertension: blood pressure ≥ 140/90 mmHg, first detected during pregnancy and return to normal blood pressure within 12 weeks after delivery, without urinary protein, patients may be accompanied by epigastric discomfort or thrombocytopenia, and the diagnosis is confirmed only after delivery.
(2) Pre-eclampsia: divided into mild and severe pre-eclampsia. Mild: blood pressure ≥140/90mmHg, urinary protein ≥0.3g/24h or urinary protein (+) for the first time after 20 weeks of pregnancy; severe: those who achieve any one or more of the following: blood pressure ≥160/110mmHg, urinary protein (++), proteinuria ≥5.0g/24h, blood creatinine >106μmol/L, platelets <100×109/L, lactate dehydrogenase rising, liver enzymes rising, persistent headache or other neurological or visual disturbances in the brain. Patients with gestational hypertension are classified as pre-eclamptic once they develop proteinuria.
(3) Eclampsia: Pregnant women with pre-eclampsia have convulsions or coma that cannot be explained by other causes.
(4) Chronic hypertension complicated by preeclampsia: pregnant women with chronic hypertension without urinary protein, with urinary protein ≥300mg/24h after 20 weeks of pregnancy; sudden increase in proteinuria or further increase in blood pressure or presence of platelets <100×109/L after 20 weeks.
(5) Combined chronic hypertension in pregnancy: blood pressure ≥ 140/90 mmHg, hypertension diagnosed before pregnancy or before 20 weeks of pregnancy and persisting after 12 weeks postpartum.
Hypertension during pregnancy is considered an important cause of maternal and intrauterine fetal death and neonatal death. The use of antihypertensive drugs during pregnancy should take into full consideration the effects of the drugs on the mother and on the fetus through the blood of the placenta. In addition, antihypertensive drugs can cause a rapid decrease in perfusion pressure in the organs, which can lead to a low maternal cardiac output as well as a decrease in uteroplacental blood flow, potentially inducing fetal asphyxia, and therefore must be applied with caution. The aim of treatment is to enable the patient to avoid the emergency state of severe hypertension as well as chronic hypertension and to continue the pregnancy, hence the need for a gentle lowering of blood pressure.
Central antihypertensive drugs:The drug recommended by the British Hypertension Society (BHS) for the treatment of chronic hypertension in pregnancy is methyldopa, which is still the first-line drug for hypertension in pregnancy. Some antihypertensive drugs for pregnancy hypertension, such as beta-blockers, peripheral vasodilators and calcium antagonists, are often used as control drugs.
Calcium antagonists:It is still controversial whether the use in early pregnancy (within 3 months) increases the risk of fetal malformation. However, when nifedipine is used to treat hypertension in pregnancy, it has a moderate antihypertensive effect, does not reduce cardiac output, and has the effect of suppressing contractions. Some studies have shown that nifedipine does not affect labor or increase postpartum hemorrhage and can be used as a first-line antihypertensive drug. Reports suggest that when administered sublingually or intravenously, the rapid and excessive drop in blood pressure has led to myocardial infarction or fetal distress. Therefore, there is a preference for smooth BP lowering with controlled or extended release dosage forms. Newer generation drugs such as irradipine, nimodipine, and nicardipine are highly vasoselective and have weak effects on uterine contractions during and after delivery and can be used more confidently in the treatment of hypertension in pregnancy. However, it should be noted that calcium antagonists should not be combined with magnesium sulfate, which is commonly used in the treatment of eclampsia, because the effect of magnesium sulfate can be enhanced by calcium antagonists, which may lead to sudden and severe hypotension.
Beta-blockers: They have proven effectiveness in gestational hypertension and are considered safe for short-term use in the second trimester. However, they can cause intrauterine growth retardation, neonatal respiratory disturbances and hypoglycemia because they can pass through the placenta and reduce the blood supply to the uterus and placenta. Indololol and atenolol have these effects and should not be used in the early and middle stages.
Vasodilator:Hydrazinepyridazine is a direct vasodilator drug, which has obvious dilating effect on small arteries and reduces diastolic blood pressure, does not affect the uteroplacental circulation and has no adverse effect on the fetus. Intravenous medication is used abroad as the drug of choice for severe hypertension in pregnancy.
Diuretics:The hypotensive effect is relatively weak, and the application of diuretics in early pregnancy prevents maternal blood volume from expanding to normal gestational levels, which may contribute to the occurrence of pre-eclampsia. Thiazide diuretics have the presence of adverse reactions leading to fetal and neonatal jaundice, hypokalemia, thrombocytopenia, etc. In principle, excessive use should be avoided.
Angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II receptor antagonists (ARB):Used in mid- and late-term pregnancy, ACEI can lead to fetal abnormalities, such as low amniotic fluid, pulmonary insufficiency, fetal growth retardation, renal insufficiency, neonatal anuria and neonatal death. ARB should not be used during pregnancy because it can lead to fetal malformation and stillbirth.
2. Diabetes mellitus
Gestational diabetes mellitus (GDM) refers to varying degrees of glucose tolerance abnormalities that occur or are first detected during pregnancy.
Effects of pregnancy on diabetes: Pregnancy increases the demand for insulin in pregnant women. Pregnancy makes the diagnosis and treatment of diabetes more difficult: loss of appetite and violent vomiting in early pregnancy; increased physical exertion and reduced eating during delivery, resulting in large amounts of glycogen depletion; sudden decrease in insulin requirement after delivery due to delivery of the placenta; lowered renal sugar excretion threshold, urine sugar cannot accurately reflect the condition; easy to cause complications such as ketoacidosis and hypoglycemia.
Effects of diabetes on pregnant women: high incidence of hypertensive disease during pregnancy; high incidence of infection, which is likely to cause ketoacidosis; other obstetric complications: excess amniotic fluid, amniotic membrane infection, premature rupture of membranes, preterm labor, etc.; high rate of postpartum hemorrhage.
Effects of diabetes on fetus: high incidence of giant fetus; high incidence of malformed fetus; high incidence of fetal growth restriction, fetal distress and stillbirth.
Effects of diabetes on the newborn: high incidence of neonatal hypoglycemia; high incidence of neonatal respiratory distress syndrome.
(1) Dietary nutrition therapy is very important for GDM patients, some GDM patients only need dietary nutrition control to maintain blood glucose in the normal range, so all GDM mothers should receive nutritional counseling from a nutritionist as much as possible to develop an individualized nutrition treatment plan.
(2) Exercise therapy for GDM has received widespread attention and recognition. Women who maintain regular exercise before and during pregnancy can reduce the occurrence of GDM. Appropriate exercise can also reduce the chance of developing type 2 diabetes after delivery in pregnant women with GDM.
(3) For patients with GDM that cannot be controlled by dietary and nutritional therapy, insulin is the main treatment drug.
(4) The treatment of GDM with oral hypoglycemic drugs is still controversial. Due to the special nature of medication in pregnancy, oral hypoglycemic therapy has been listed as a contraindication in pregnancy. Previous studies have concluded that oral hypoglycemic agents should be contraindicated in pregnancy because of their increased risk of fetal malformations. However, a growing number of new findings suggest that some oral hypoglycemic agents are safe and effective for pregnant women with diabetes.
In 2009, the American College of Obstetricians and Gynecologists (ACOG) reported that 13% of OB/GYNs in the United States currently use glibenclamide as a first-line agent for GDM.
3.Cold
General cold, the symptoms are mild, such as runny nose, sneezing, the impact on the fetus is not significant, and there is no need to take medicine, rest for a few days will be fine. But in the early stages of pregnancy (5-14 weeks), mainly the time of fetal embryonic development organ formation, if suffering from influenza, and the symptoms are heavy, it will have a greater impact on the fetus, during this period to take drugs also have a greater risk to the fetus.
For mild colds, you can use pure Chinese medicine such as Banlangen Punch. Drink more water and take rest, and the cold will be cured soon.
For high fever and severe cough, you can use Chai Hu injection to reduce fever and pure Chinese medicine cough syrup to stop coughing. At the same time, you can also use wet towels to apply cold compresses, and use about 30% alcohol (or white wine to dilute twice) to rub the bath to play a physical role in relieving fever.
Anti-viral drugs all have adverse effects on the fetus, pregnant women should not use, if you must use, there should be a doctor’s guidance. The anti-inflammatory pain is a contraindicated antipyretic for pregnant women, and aspirin should not be used after 32 weeks of pregnancy. Expectorants and cough medicines are generally safe, but cough medicines containing iodine preparations should not be used by pregnant women.
4.Vitamins
According to the FDA classification standards, for pregnant women, the same drug (referring to certain drugs) can have two different levels of harm, the harm is due to the different doses of drugs, one is the level of the usual dose, and the other is the level of the extraordinary dose. For example, vitamin A, the normal dosage is a class A drug, which is safe for pregnant women, the daily dosage of vitamin A for pregnant women does not exceed 5,000 U, while large doses of vitamin A, the daily dose of more than 15,000 U, can be teratogenic, and become a class X drug, class X drugs are prohibited for women who are pregnant or will be pregnant. Large doses of vitamin D can cause fetal hypercalcemia and retarded mental development. Large amounts of vitamin K can cause fetal hyperbilirubinemia and nuclear jaundice. Large amounts of vitamin B6 can cause vitamin B6 dependence and convulsions in newborns.
V. Principles of safe drug use during pregnancy
1. Do physical examination before pregnancy and strive for pregnancy in a healthy state.
2, the application of any drug must be taken under the guidance of doctors, pharmacists.
3.If a chronic disease is found before pregnancy, take into account the continuity and safety of medication during pregnancy and avoid using drugs that may endanger the fetus.
4, early pregnancy (within 12 weeks) try not to use drugs.
5, try to avoid the combined use of drugs.
6.Use drugs with more positive conclusions and avoid using new drugs.
7, do not use their own random drugs or listen to the fetish, secret recipe to prevent accidents.
8, when using drugs, pay attention to the words of caution, contraindicated and prohibited for pregnant women on the bag.
9, must use drugs, try to choose no damage to the fetus or the impact of small drugs.
10.After a pregnant woman has mistakenly taken a teratogenic or potentially teratogenic drug, she should consider whether to terminate her pregnancy under the guidance of a doctor and according to the time of pregnancy, the amount of medication and the time of medication.
11. Most of the instructions of proprietary Chinese medicines are simple, and many of them do not contain any precautions for pregnant women. As it is difficult to weigh the pros and cons of pregnant women’s medication, they should be used with caution to ensure the safety of medication.
Sixth, the correct treatment
In fact, the probability of teratogenic drugs is very small, and obstetricians need to pay attention to both the effect of the disease itself on the fetus and the effect of drugs on the fetus. Sometimes the effect of the disease itself on the fetus is more serious. The doctor’s medication is a process of weighing the pros and cons, and both the doctor and the patient should consider the risk of treating the disease and the risk of not treating it.
In conclusion, there are almost no medications that are absolutely safe for treatment during pregnancy, so unnecessary medications should be avoided, especially in early pregnancy. For possible adverse reactions to medication, preventive measures should be taken as far as possible to reduce the degree of harm to the fetus and the pregnant woman.