: Placental insufficiency is a common and serious complication of the placenta during pregnancy, which affects about 10 to 15% of pregnancy. Placental insufficiency is one of the common clinical problems in obstetrics for mothers and fetuses because it is still a potential cause of preterm birth, preeclampsia, fetal growth restriction, and stillbirth. In the case of placental insufficiency, the placenta cannot provide enough oxygen and nutrition from the mother's blood to the fetus, which leads to fetal growth restriction, intrauterine fetal distress, low birth weight, stillbirth, neonatal asphyxia, or some birth defects later. Doppler ultrasound is a common method to evaluate the degree of placental blood circulation damage. However, until now, there is no consensus on the standard definition, specific diagnostic criteria, and common treatment guidelines for placental insufficiency.
Aim: to analyze the effects of drugs (low-molecular weight heparin in single therapy and fluids rehydration therapy in single or combination therapy) on ultrasonic Doppler blood flow indices and pregnancy outcomes of placental insufficiency in the third trimester of single pregnancies.
Materials and Methods: 120 single pregnant Chinese women were included in this study from September 2019 to December 2020. 60 pregnant women with a high S/D ratio of the fetal umbilical artery in late single pregnancy were studied retrospectively as the case group, and 60 normal pregnant women with a normal S/D ratio of the fetal umbilical artery were taken as the control group in the same period. Among the cases, 22 cases were treated with low-molecular-weight heparin (LMWH), 16 were treated with maternal fluids replacement therapy (FRT), and the others 22 were treated with LMWH + FRT. After 10 days of medication, the Doppler ultrasound blood flow indices (S/D ratio of the fetal umbilical artery and PS, PI, RI of the middle cerebral artery) were observed, and the indices before and after treatment were compared to observe the effectiveness of these drugs. Meanwhile, the pregnancy outcomes of the case group (n=60) and the control group (n=60) were recorded and compared .
Results: The study found that the mean S/D ratio of fetal umbilical artery in case group and control group was respectively 3.46±0.45 and 2.18 ±0.34, P-value= 0.000, had statistical significance before treatment; and was respectively 2.57 ±0.76 and 2.29 ±0.34, P-value = 0.000 was statistically significant too after treatment, which indicates that the S/D ratio of the fetal umbilical artery has significant significance in the evaluation of placental insufficiency. Further analysis showed that the women treated with low-molecular-weight heparin (LMWH), the mean value of S/D ratio of fetal umbilical artery before and after LMWH treatment was respectively 3.26± 0.84 and 2.25 ±0.25; the mean value of S/D ratio in the fetal umbilical artery before and after treatment was significantly different, which indicates that LMWH alone had a certain effect on improving fetal umbilical blood flow. For the women treated with fluids replacement therapy (FRT), the mean value of S/D ratio of fetal umbilical artery before and after treatment was respectively 3.07± 0.86 and 2.93 ±0.66; there was no significant difference in the mean value of S/D ratio between the two groups before and after treatment, FRT alone has little significance in reducing the ratio of S/D of the fetal umbilical artery, indicating that the effect of FRT alone was not good, and effective as other drugs. For the women treated with low-molecular-weight heparin+ fluids replacement therapy (LMWH+FRT), the mean value of S/D ratio of fetal umbilical artery before and after treatment was respectively 3.12± 1.16 and 2.60 ±0.76; the mean value of S/D ratio in fetal umbilical artery before and after treatment was significantly different, which indicates that LMWH + FRT was more effective than single FRT, and the effect was similar to that of LMWH alone. Furthermore, Compared with the normal control group, the mean value of fetal and maternal outcomes in the case group was low, which indicates that pregnant women in the case group are more likely to have a variety of adverse fetal and maternal outcomes, such as premature delivery, low fetal weight during delivery, small gestational week, low Apgar score during delivery; We also found that the incidence of premature delivery, cesarean section, low Apgar score (< 6), amniotic fluid abnormality, placental morphology abnormality, cord abnormality, low birth weight (< 2500g), neonatal asphyxia, stillbirth and NICU admission was higher than those in the normal control group.
Conclusion: Low-molecular-weight heparin (LMWH) alone or a combination of low-molecular-weight heparin and fluids rehydration therapy (LMWH + FRT) as a potential treatment of placental insufficiency in late single pregnancies can significantly reduce the S/D ratio of the fetal umbilical artery, suggesting that, it has a significant effect on the improvement of placental function. Moreover, fetal and maternal adverse pregnancy outcomes were associated with placental insufficiency in the third trimester of single pregnancies.