If I use a certain medicine during pregnancy, will it affect the development of the embryo?
What medications can I take if I have a cold during pregnancy?
What is the safest time to take medication during pregnancy?
Is it possible to detect any embryonic abnormality caused by certain drugs taken during pregnancy?
These questions are frequently encountered by obstetricians and gynecologists and are answered as follows.
I. Typical tragedies of medication in early pregnancy.
In the 1950s, a drug called “Reaction Stop” was popular for the treatment of pregnancy vomiting. The main ingredient of this drug is ethylene estradiol. Forty years ago, an article was published in the New England Journal summarizing this event. This event reminds us that medication during pregnancy needs to be used with great caution!
II. The use of medication during pregnancy needs to be brought to your attention as follows.
1. Perhaps a drug may be safe in the short term, but the long-term effects cannot be assessed.
2, most drugs have not been tested on humans, and the so-called safety is relative.
3. Even if a drug used during pregnancy has an effect on embryonic development, this effect may not always be detected during pregnancy. At present, only a limited number of diseases can be detected, and malformations are limited to relatively large malformations.
4. For most drugs, no doctor can ensure that they have no effect on embryonic development.
3. The relationship between the number of weeks of gestation and fetal malformations
The timing of drug exposure during pregnancy is closely related to fetal malformations. Drug-induced fetal malformations basically occur 5-11 weeks after menopause, (3-9 weeks after fertilization). This is because this period is the period of fetal organ formation.
The sensitive time for various organs to be affected by substances.
1. heart: 20-40 days after fertilization
2. limbs: 24-46 days after fertilization
3.External genitalia: 36-55 days
4.Eyes: 24-39 days.
During the 1-2 weeks of fertilization, which is the period of oogenesis, the fertilized egg has a strong compensatory capacity, and after this period is affected by drugs, the embryo either develops normally or dies (miscarriage); during the 3-8 weeks after fertilization, which is the period of intensive formation of various organs, it is a sensitive period for the occurrence of malformations, although the sensitivity of each organ differs in time and degree; from the 9th week of fertilization to birth, which is the period of functional development of various organs From the 9th week of fertilization to birth is the period of functional development of each organ, which is not sensitive to malformations, but the nervous system and reproductive organs are still sensitive. For example, abnormal behavior, abnormal organ function, developmental delay, etc.
Commonly used drugs that are contraindicated in pregnancy
Androgens, ethylene estradiol, mifepristone, tamoxifen, ethanol, radioactive iodine, warfarin, methotrexate, cyclophosphamide, retinoic acid, streptomycin, kanamycin, leucovorin, phenytoin, isotretinoin, etc.
V. Medication for certain common diseases during pregnancy.
1. Hyperthyroidism: According to the American Thyroid Association guidelines, propylthioxypyrimethamine (PTU) is advocated in early pregnancy. This drug is less likely to cause malformations because it does not easily pass through the placenta in early pregnancy, but it is likely to cause liver damage. In mid- to late-pregnancy, tapazole is recommended because it causes scalp defects in the embryo in early pregnancy. In the middle and late stages, there is no such effect.
2, emergency contraceptive drugs: investigation shows that yutin failure can not cause adverse fetal prognosis, mifepristone may have adverse effects on the fetus.
3, hypertension: angiotensin inhibitors (ACEI) cause cardiac or neural tube malformations, other antihypertensive drugs are relatively reduced risk.
4, diabetes: the application of insulin and metformin during pregnancy did not see adverse effects.
5, isotretinoin caused 50% of miscarriage, or cause fetal cardiac malformation or neurological malformation.
6. Warfarin caused 20% of fetuses to develop Warfarin syndrome.