When mummy-to-be is short in stature, there’s usually the prediction that baby will be little, too – quite simply because a smaller uterus means limited growing space.
But a recent study reveals that a mother’s height directly influences not just the size of her bambino, but also how long she stays pregnant, leading to a better understanding of preterm birth and why it happens.
New research published today in the journal PLOS Medicine finds that not only do shorter women have babies with lower birth weights and lengths—but the length of the gestational periods are actually shorter as well.
Scientists at the March of Dimes Prematurity Research Center Ohio Collaborative studied over 3,000 women and found an interesting correlation between mothers’ heights and babies who were born early. “As part of our genetic studies of factors that increase the risk for preterm birth, we collect other information about the mothers, such as their height, weight and age,” study author Dr. Louis Muglia, M.D., Ph.D., co-director of the Perinatal Institute at Cincinnati Children’s Hospital Medical Centre. “We found when we ran our analysis that mum’s height was a risk factor for having a preterm birth, so we decided to investigate this further.”
What the researchers discovered was something beyond the expected link between a mum’s height (and thus uterine ‘holding capacity’) and baby’s birth weight and measurements; whatever influences maternal height, such as genes – but also – nutrition and metabolic processes, affects the duration of a pregnancy. In other words, a mother’s height tends to correlate with lowered metabolic function, and this might mean less energy being made available to the developing foetus – so preterm birth could be a possibility in such a case.
Gestational length is controlled by more than the mother’s genes, and whatever it was that makes the woman short also generates a shorter gestational length,” Joe Leigh Simpson, M.D., March of Dimes’s senior vice president for Research and Global Programs, tells Fit Pregnancy. “Presumably her height reflected other things that had gone on in the mother’s lifetime—her nutritional status or exposure to pollution, for example.”
While the study’s findings are obviously important because they are helping doctors get to the root of what causes preterm birth – particularly in the developing world, there’s no reason to panic if you’re a little (or a lot) on the short side.
Simpson says: “We know that many women in very unfavourable situations—stress, pollution, poor nutrition—still deliver at full term; they just have a higher risk of not making it to full term. Height is a part of the puzzle. But pregnancy is a very robust phenomena. Otherwise nobody who’s short would ever have a full term pregnancy!”