Promoting awareness of neonatal menstruation

Abstract

Neonatal uterine bleeding (NUB) has been carefully studied in the past through case reports, small series, clinical cohort studies, pathology investigations of fetal and neonatal. Following a historical recount, this review summarizes biological mechanisms conditioning NUB, starting from the persistence till birth of an 'ontogenetic progesterone resistance' (OPR), causing decreased responsiveness of target tissues to bioavailable progesterone. Several pregnancy-related conditions, such as preeclampsia, fetal growth restriction, prematurity, post-maturity and even Rhesus or ABO incompatibility, influence the occurrence of NUB. It seems therefore that the phenomenon is precipitated by chronic fetal distress. When present, OPR may persists until telarche; as a consequence, if pregnancy occurs in early teenage, the disorder known as “defective deep placentation” may ensue, increasing the risk of obstetrical syndromes. In the presence of NUB, retrograde shedding into the peritoneal cavity of endometrial stem/progenitor and niche cells may occur. There, given the right environment, these cells can survive and become activated at the time of telarche, causing the specific phenotype of early-onset endometriosis. In conclusion, neonatal menstruation is a fetal distress indicator and can alter the incidence of a variety of pathological conditions later in life. For this reason, it should be carefully recorded and the parents informed.

Chinese abstract

既往的病例报告、小规模系列研究、临床队列研究和胎儿和新生儿的病理学研究中详细研究了新生儿子宫出血 (NUB) 。该综述根据历史记录总结了调节NUB的生物学机制, 从持续性到”个体发育孕激素拮抗” (OPR) 的开始, 导致靶组织对具有生物活性的孕酮的反应性降低。一些孕期相关的条件比如先兆子痫、胎儿生长受限、早产、胎儿过度成熟、甚至RH或ABO溶血, 均会影响NUB的发生。似乎这种现象是由慢性胎儿窘迫所致。我们提出, OPR可以持续到乳房早期发育期;因此, 如果妊娠发生在青少年早期, 可能会发生称为”胎盘深层缺陷”的障碍, 增加产科并发症的风险。在NUB的存在下, 可发生子宫内膜干/祖细胞和小细胞逆行脱落到腹膜腔中。给予正确的环境, 这些细胞可以生存并在乳房初期发育时激活, 导致早期子宫内膜异位症的特定表型。总之, 新生儿月经是一项胎儿窘迫的指标, 可以改变后期生活中各种疾病的发生率。因此, 应详细记录, 并告知家长。

Keywords:

• Endometriosis
• fetal growth restriction
• neonatal menstruation
• prematurity
• preeclampsia

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.