The impact of gestational diabetes and hypothyroidism on the third-trimester ultrasound parameters and in adverse perinatal outcomes: a retrospective cohort study.

Objective: To assess the impact of gestational diabetes and hypothyroidism on the third-trimester ultrasound parameters and in adverse perinatal outcomes.

Methods: We performed a retrospective cohort study with 817 singleton pregnant women between 26w0d and 37w6d of gestation which were divided in four groups: 56 gestational diabetes mellitus (GDM), 63 hypothyroidism, 14 GDM + hypothyroidism, and 684 controls. The following ultrasound parameters were assessed: mean uterine artery pulsatility index (PI), umbilical artery PI, middle cerebral artery PI, single deepest pocket (SDP) and cerebroplacental ratio (CPR). Adverse perinatal outcomes were the following: low birth weight, macrosomia, and Agar score at 1st min <7. These four groups were compared using the Kruskall-Wallis and χ(2) tests.

Results: Pregnant women from GDM showed higher weight (p < 0.001), BMI (p < 0.001), SDP (p < 0.001) and newborns with higher birth weight (p = 0.008) and macrosomia (p = 0.02) than other groups. Comparing with control, hypothyroidism showed higher SDP (p < 0.05).

Conclusion: Pregnant women with GDM showed higher risk of macrosomic newborns than other three groups. Both pregnant women with GDM and hypothyroidism showed higher SDP than normal pregnancies.