# Mediating effect of gestational weight gain on the preventive effect of exercise during pregnancy on macrosomia: a randomized clinical trial

## TL;DR

A study found that individualized exercise during pregnancy reduces macrosomia risk, with gestational weight gain acting as a mediator.

## Contribution

This study identifies gestational weight gain as a mediator in the preventive effect of exercise on macrosomia.

## Key findings

- Individualized exercise guidance significantly reduced macrosomia incidence compared to standard care.
- Gestational weight gain was found to mediate the effect of exercise on reducing macrosomia.
- Exercise did not increase preterm birth rates or affect gestational age at birth.

## Abstract

We sought to investigate the impact of individualized exercise guidance during pregnancy on the incidence of macrosomia and the mediating effect of gestational weight gain (GWG).

A prospective randomized clinical trial.

A Hospital in Xingtai District, Hebei Province.

Older than 20 years of age, mid-pregnancy, and singleton pregnant women without contraindications to exercise during pregnancy.

A randomized clinical trial was conducted from December 2021 to September 2022 to compare the effects of standard prenatal care with individualized exercise guidance on the incidence of macrosomia.

Incidence of macrosomia.

In all, 312 singleton women were randomized into an intervention group (N = 162) or a control group (N = 150). Participants who received individualized exercise guidance had a significantly lower incidence of macrosomia (3.73% vs. 13.61%, P = 0.002) and infants large for gestational age (9.94% vs. 19.73%, P = 0.015). However, no differences were observed in the rate of preterm birth (1.86% vs. 3.40%, P = 0.397) or the average gestational age at birth (39.14 ± 1.51 vs. 38.69 ± 1.85, P = 0.258). Mediation analysis revealed that GWG mediated the effect of exercise on reducing the incidence of macrosomia.

Individualized exercise guidance may be a preventive tool for macrosomia, and GWG mediates the effect of exercise on reducing the incidence of macrosomia. However, evidence does not show that exercise increases the rate of preterm birth or affects the average gestational age at birth.

The trial is registered at www.clinicaltrails.gov [registration number: NCT05760768; registration date: 08/03/2023 (retrospectively registered)].

The online version contains supplementary material available at 10.1186/s12884-024-06527-7.