Handgrip strength during pregnancy: A first reference values based on nationally representative survey.

Objective: Handgrip strength (HGS) using isometric dynamometry is a convenient and feasible noninvasive measure of physical strength, overall health, and nutritional status among people of all ages. While adult HGS norms have been published in many countries, no study has synthesized available data to produce representative norms during pregnancy. This study used data from an extensive national representative survey to generate gestational age-specific reference norms for HGS during pregnancy.

Methods: This cross-sectional study enrolled 1016 pregnant women aged 18-48 years old. HGS was measured using a hand dynamometer with an adjustable grip. Smoothed centile curves and tables for the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles were calculated using lambda-mu-sigma (LMS) method to develop gestational age-specific norms for absolute HGS (in kilograms [kg]) and HGS normalized by height (Ht) in meters (m) squared (i.e., HGS/Ht2 in kg/m2).

Results: We found no significant difference in absolute or normalized grip strength between trimesters and gestational weeks (p > 0.05). Median (P50), absolute and normalized HGS levels improved negligibly (equivalent to ∼0.3-1.4 kg for absolute HGS or ∼0.1-0.5 kg/m2 for normalized HGS) throughout early pregnancy (1-4 weeks to 14-17 weeks) and peaked from gestational age 23-27 weeks (at 22.97 kg [absolute HGS] or 8.74 kg/m2 [normalized HGS]) However, the gestational age-related decline in HGS levels was slightly smaller for young women than for women during middle adulthood.

Conclusions: This study provides the first national norms for pregnant women with HGS according to the gestational age. These norms are useful for health screening, monitoring, and surveillance, and for comparison with studies from other countries.