Influence of assisted reproductive technologies on maternal and neonatal outcomes in early preterm deliveries

Compared to spontaneous conception (SC), pregnancies conceived through assisted reproductive technologies (ART) carry worse pregnancy and neonatal outcomes. Evidences focused on preterm births are limited. Early preterm delivery is a critical situation for medical management and parental counselling. The aim of this study was to analyze if ART procedures influenced pregnancy and neonatal outcomes in singleton pregnancies with early preterm delivery.

This was a retrospective case control study. The population consisted of all consecutive early preterm deliveries occurred at Careggi University Hospital in Florence (Italy) between 2010 and 2017. Cases were considered patients who conceived though ART, including intra cytoplasmic sperm injection (ICSI), in vitro fertilization and embryo transfer (IVF-ET), intra uterine insemination (IUI) and ovarian stimulation. Controls were patients who conceived in the natural way. Main outcomes of the study were: birth weight, umbilical artery pH, Apgar score at 1 and 5 min, gestational age at delivery and mode of delivery. Secondary outcomes were: spontaneous preterm labor initiation, gestational diabetes mellitus, intrauterine growth restriction (IUGR), cholestasis of pregnancy, intra uterine fetal demise (IUFD), placenta previa, fetal malformations, pregnancy induced hypertensive (PIH) disorders (gestational hypertension, preeclampsia and hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome) and postpartum hysterectomy. Shapiro-Wilk test was used to check the normality of the data; Mann-Whitney test was used to compare two continuous variables not-normally distributed. Multiple and binomial logistic regression analyses were used to adjust the results of the statistical analysis for potential confounding factors. The analysis for the main outcomes was performed for all deliveries and then repeated for spontaneous deliveries, separately.

Seventy-one patients had ART and 640 SC. We found no differences in birthweight, umbilical artery pH, Apgar at 1 and 5 min and gestational age at delivery between ART and SC groups. C-section rate, placenta previa and PIH disorders were higher in the ART group. The higher prevalence of C-sections in the ART group was not statistically significant after adjusting for age and parity in the whole population but resulted significantly different when analyzing the subgroup of patients with spontaneous initiation of labor.

Fetal outcomes seem to be equal between ART and SC in early preterm neonates ; C-section rate and pregnancy complications such as placenta previa and PIH disorders seem to be higher in the ART group. These information should be part of the family counselling in these cases. We suggest that clinicians, after management of preterm delivery had been properly addressed, should not apply different management in ART compared to SC pregnancies.