Fertility, body size, and shape: An empirical test of the covert maternal depletion hypothesis

Abstract

In populations with limited resources, high-reproductive effort may lead to poor nutritional status of the mother (the maternal depletion syndrome), whereas in well-nourished populations woman's body weight tends to increase after each pregnancy. However, in affluent populations, women's body shape may change due to mobilization of polyunsaturated fatty acids (PUFAs) from the lower parts of their bodies to meet the needs of the developing child (the "covert maternal depletion"). We studied relationships between reproductive history traits and body size and shape for 296 rural, parous women in good nutritional status (mean body mass index, BMI = 27.9, SD = 5.94), aged 22-85 (mean 47.8, SD = 16.34) from southern Poland. Body mass adjusted for age, age of menarche, body height, and similarly adjusted BMI were each positively related to the number of children born by a woman (R = 0.13, P = 0.02 and R = 0.13, P = 0.02, respectively). Waist and hip circumferences, adjusted for confounders, did not show statistically significant relationships with the number of children. Moreover, groups with low and high parity did not significantly differ in hip/BMI and waist/BMI ratios, which were proposed to be indicators of covert form of maternal depletion (after controlling for overall body fatness and age). In conclusion, parity caused a slightly higher body mass and BMI later in life. However, parity did not lead to covert maternal depletion, perhaps because women in this population have relatively high-dietary intake of PUFAs.