Difference in the size of the placenta and umbilical cord between women with natural pregnancy and those with IVF pregnancy

Atsushi Yanaihara, Shota Hatakeyama, Shirei Ohgi, Kenichirou Motomura, Ryoma Taniguchi, Aguri Hirano, Shin Takenaka, Takumi Yanaihara

The purpose of this study was to compare the sizes of the placenta and umbilical cord in women with natural pregnancy versus those undergoing in vitro fertilization (IVF). Overall, 1610 cases of uncomplicated single pregnancies with vaginal delivery at ≥ 37 weeks of gestation were included in this study. The patients were divided into two groups: natural pregnancy group (n = 1453) and IVF pregnancy not including intracytoplasmic sperm injection (ICSI) treatment (n = 157). The groups were compared in terms of gestational week, maternal age, parity, maternal weight gain, prepregnancy maternal BMI, infant weight at birth, infant head circumference, placental weight, cross section of the placenta, cross section of the umbilical cord, insertion site of the umbilical cord, and umbilical cord length. Stepwise selection and multivariate logistic regression were used for statistical analysis to correct the result as an independent factor. There was no difference in the size of the placenta and umbilical cord between women with natural pregnancy and with IVF, but the incidence of velamentous insertion of the cord was significantly increased in women with IVF pregnancy (adjusted odd ratio [AOR] 1.72, 95% confidence interval [CI] 1.08-2.72, p = 0.026). Although there is no difference in placental weight and cord size, velamentous insertion of the umbilical cord increases in IVF pregnancy and needs careful observation during the delivery process.