Maternal Height, Pre-Pregnancy BMI, Weight Gain Affect Adverse Pregnancy Events

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The link between maternal height and adverse pregnancy outcomes varies with pre-pregnancy body mass index (BMI) and gestational weight gain in women with gestational diabetes mellitus, according to new data.

Height plays a role in pregnancy-inducted hypertension, macrosomia, preterm birth, and maternal and fetal metabolic disorders. Height, along with weight, also affects the mode of delivery and adverse pregnancy outcomes. For instance, short height is linked to preterm birth, hypertension, fetal growth restriction, and cesarean delivery.

A new retrospective study, led by Mengkai Du, of the obstetrical department at Zhejiang University, in Hangzhou, China, sought to evaluate the association between maternal height and adverse events in women with gestational diabetes mellitus. The investigators also stratified for gestational weight gain and BMI.

The investigators clarified gestational weight gain and pre-pregnancy BMI have “independent effects on pregnancy outcomes.” A previous study found shorter women with pre-pregnancy obese BMI had a 3 times higher risk of macrosomia compared to shorter women with normal or overweight pre-pregnancy BMI.

The study included 2048 women diagnosed with gestational diabetes mellitus from July 2017 – June 2018, in Zhejiang Province, China. They were diagnosed using a 75 g oral glucose tolerance test at 24 – 28 gestational weeks. The study included women who received prenatal care and gave birth to a livebirth singleton of >28 gestational weeks at Women’s Hospital, Zhejiang University School of Medicine.

The investigators defined preterm neonates as newborns with a gestational age ≥ 28 weeks but <37 weeks. Newborns who weighed ≥ 4000 g were considered to have macrosomia, and newborns who weighed < 25000 g were considered to have a low birth weight. A postpartum hemorrhage referred to blood loss ≥ 500 ml after vaginal delivery or ≥ 1000 ml after c-section. Also, the investigators divided maternal height into 3 categories: shorter (≤158 cm), average (between 158.1 – 162.0 cm), and taller (>162.0 cm).

Ultimately, the investigators noted differences in gestational diabetes mellitus (P = .006), pre-pregnancy weight (P = .001), birthweight (P = .001), birth length (P <.001), neonatal ponderal index (P <.001). Specifically, they found differences in abnormal neonatal ponderal index, macrosomia, postpartum hemorrhage, primary C-section, and low birth weight. Also, there was no difference in pre-pregnancy BMI, maternal age, parity, HbA1c, fasting plasma glucose, 1 h-PG or 2 h-PG among the height categories.

The investigators found shorter women had higher rates of low birth rate (P = .003) and primary (first time) c-section (P <.001). Meanwhile, taller women had higher rates of abnormal neonatal ponderal index (P <.001), postpartum hemorrhage (P = .044), and macrosomia (P <.001). For taller women with excess gestational weight gain, maternal height was positively associated with the risk of macrosomia (adjusted odds ratio [aOR], 1.97; 95% CI, 0.95 – 4.10). Though for shorter women with inadequate gestational weight gain, maternal height was significantly linked with low birth weight.

For shorter women with excess gestational weight gain, height was a factor of postpartum hemorrhage (aOR 0.15, 95% CI, 0.03 – 0.72). Moreover, for women with normal pre-pregnancy BMI, height was positively linked with low birth weight (aOR 2.00; 95% CI, 1.15 – 3.49) and primary c-section (aOR 1.71; 95% CI, 1.28 – 2.28) in shorter women.

“Our findings suggest that maternal height can be used as a reference to identify Chinese women at high risk of adverse outcomes; however, pre-pregnancy BMI and [gestational weight gain] should be considered,” the investigators wrote.

^References

^{Du, M., Muhuza, M.P.U., Tang, Y. et al. Maternal Height Is an Independent Risk of Adverse Outcomes in Women with Gestational Diabetes Mellitus. Diabetes Ther (2023). https://doi.org/10.1007/s13300-023-01512-3}