Multiple fetal pregnancy reduction (MFPR) is a new technique developed in response to the significant increase in the incidence of multiple pregnancies in recent years. During pregnancy, MFPR reduces the number of fetuses in a multiple pregnancy to allow for successful delivery of the retained fetus. Numerous studies have confirmed that MFPR can successfully reduce the number of fetuses in multiple pregnancies, especially the maternal obstetric complications and perinatal mortality in pregnancies with more than 4 fetuses; moreover, a low miscarriage rate can be maintained after MFPR operation. Therefore, MFPR can be considered as a relatively safe and effective method to improve the prognosis of multifetal pregnancies.
MFPR can achieve both the goal of fertility and reduce the risk and poor prognosis of multiple pregnancies.
Indications for MFPR
1. Ultrasound confirmed reduction of early pregnancies with > or =3 fetuses to twins in general, or to singleton due to comorbidities;
2. Selective reduction of fetal abnormalities after prenatal diagnosis in early or mid-pregnancy to preserve normal fetuses.
The main methods of MFPR are
1.Cardiac puncture to stop the heart by physical trauma;
2. Cardiac puncture with injection of drugs such as potassium chloride and lidocaine;
3.Intra-amniotic injection of hypertonic saline;
4.Early pregnancy (6-8 weeks) puncture needle with negative pressure to aspirate embryonic tissue.
Disadvantages: high abdominal muscle tension, the direction of needle tip activity is not easy to grasp, and the operation is time-consuming.
Transvaginal route
At 7 weeks of gestation, fetal buds and primordial ventricular pulsations are visible on vaginal ultrasound, so reduction is feasible at 7-8 weeks of gestation. The fetal sac is accessed through the vaginal wall and uterine wall under real-time transvaginal ultrasound guidance, and the fetal heartbeat area is punctured and potassium chloride is injected. Or the embryonic heartbeat can be stopped by mechanical disruption through negative pressure aspiration or repeated stabbing. The transvaginal route is early in diagnosis, the injection volume is small, no bladder filling is required, the ultrasound image is clear, and the operation is highly accurate.
Choice of gestational bursa reduction
1.Select a gestational sac that is convenient for operation;
2.Select the gestational sac containing the smallest fetal body;
3.Select the gestational sac that is close to the cervix.
Timing of MEPR
With the increasing sophistication of the technique, the overall abortion rate is the same for reduction performed in early, middle and late pregnancy. However, for pregnancies with 4 or more fetuses, the miscarriage rate of early reduction is low. Geva et al. (2000) concluded in a comparative study of 38 cases of mid-trimester reduction and 70 cases of early-trimester reduction that mid-trimester reduction also resulted in satisfactory perinatal outcomes and facilitated the detection of fetal structure and chromosomal abnormalities before reduction to achieve a truly selective reduction. The results of this study suggest that midtrimester reduction is also associated with satisfactory perinatal outcomes and facilitates the detection of fetal structure and chromosomal abnormalities prior to reduction, allowing for true elective reduction.
Timing of fetal reduction
Geva et al. (2000) concluded from a comparative study of 38 cases of midtrimester reduction and 70 cases of early trimester reduction that midtrimester reduction can also achieve satisfactory perinatal outcomes and facilitate the detection of fetal structure and chromosomal abnormalities prior to reduction to achieve truly elective reduction.
Miscarriage rate of fetal reduction
The rate of fetal loss and technical proficiency can significantly reduce the rate of postoperative miscarriage
Safety of fetal reduction
The incidence of intrauterine growth retardation in retained fetuses after reduction by Deep et al. was not increased compared to normal fetuses, and the rate of miscarriage, birth weight, gestational week, and delivery route in retained fetuses after reduction by Antsaklis et al. were not significantly different from those of normal twins.
Specific methods
The number of fetal sacs was again clarified by vaginal ultrasound and a 17Gmm double-lumen needle with a thin lumen connected to 15% KCL and another tube connected to an empty 20ml syringe. Select the fetal sac with low position and easy to pass the heartbeat area by vaginal puncture into the fetal sac, 20ml syringe aspiration, if there is amniotic fluid, it proves that it has entered the fetal sac, then puncture into the fetal heartbeat area, again aspiration without amniotic fluid, it proves that the needle tip is stuck into the fetal body, slowly inject 15% KCL 0.5ml, it can be repeated 1-2 times, the amount of 15% KCL is controlled within 2ml, control the ultrasound detection during the operation The amount of 15% KCL is controlled within 2 ml, and the time of ultrasound detection is controlled during surgery.
The reduction of multifetal pregnancy can prolong the gestational week and reduce preterm delivery, and also reduce the complications of multifetal pregnancy, which is a safe and effective method.