In a recent study published in the journal PLOS One, a team of French researchers found that among children born with low birth weight (LBW) there is an increased risk of endometriosis. According to the researchers, among patients with LBW, the risk is almost two-times higher to develop deep infiltrating endometriosis (DIE).

Epidemiologic studies have found that body mass index (BMI) (association between a BMI < 18.5 and deep infiltrating endometriosis (DIE) are associated with a higher risk of endometriosis. Endometriosis may be influenced by environmental factors, especially during pregnancy. Prenatal or perinatal exposure to various external influences could induce endometrial changes in the newborn and promote the development of endometriosis later in life.

In children born with low birth weight (LBW) (i.e. weight at term delivery below 2,500g), the risk of metabolic syndrome and other vascular diseases in adulthood is well documented. There is a relationship between LBW and subsequent vascular risk, including metabolic syndrome, cardiovascular disease, type 2-diabetes and obesity in adulthood. The risk of metabolic syndrome is ten-times higher in subjects with a birth weight of less than 2,500g, compared to those with normal birth weight.

Young women being born at LBW, irrespective of gestational age, exhibit a reduction in insulin sensitivity and an increased risk of developing clinical and biochemical features of polycystic ovary syndrome.

In order to identify the potential association between birth weight and endometriosis, in their study titled “Low birth weight is strongly associated with the risk of deep infiltrating endometriosis: results of a 743 case-control study,” Dr. Borghese from the Institut Cochin, Université Paris Descartes in Paris, France, along with colleagues designed a case-control study including 368 patients with histologically confirmed endometriosis and 375 healthy controls in whom the disease was excluded by surgical examination. Birth weights were collected from medical charts for each participant.

Results revealed that when compared to controls, patients with DIE had the lowest birth weight with a highly significant difference (3,103g ± 620, p = 0.002). Statistical analyses revealed that patients with low birth weight (LBW), defined as a BW < 2,500g, had a higher risk of endometriosis, especially DIE, as compared to the reference group (OR = 1.5, 95%CI: 1.0-2.3 and OR = 1.7, 95%CI: 1.0-2.7, respectively).

The researchers also found, after adjusting for ethnicity and smoking status, that the persistence of a significant association between endometriosis and LBW with a slight increase in the magnitude of the association (aOR = 1.7, 95%CI: 1.0-2.6 for endometriosis, aOR = 1.8; 95%CI: 1.1-2.9 for DIE).

Based on these results, the researchers concluded that the association between LBW and the risk of endometriosis could reflect common signaling pathways between endometriosis and fetal growth regulation. There is also the possibility of a role played by placental insufficiency on the development of the neonate’s pelvis and the occurrence of neonatal uterine bleeding that could have consequences on the risk of severe endometriosis.