Mycoplasma genitalium infection during pregnancy may cause preterm birth

By Dr. Sanchari Sinha Dutta, Ph.D.Sep 28 2022Reviewed by Aimee Molineux

A systematic review on the impacts of Mycoplasma genitalium infection on adverse pregnancy outcomes has been published in the BMJ journal Sexually Transmitted Infections. The review found that Mycoplasma genitalium infection may increase the risk of preterm birth.

Background

Bacterial infection during pregnancy is known to increase the risk of many adverse outcomes, including spontaneous abortion, preterm birth, premature rupture of membranes, low birth weight, and perinatal death. Aberrant inflammatory response associated with bacterial infection might be responsible for these adversities, especially preterm birth. Thus, early detection of sexually transmitted infections is crucial for preventing adverse pregnancy outcomes.

Mycoplasma genitalium is a sexually transmitted bacterium causing urinary or genital tract infections. The prevalence of this bacterium among pregnant women is 1% in high-income countries and 12% in South Africa and Papua New Guinea.

Mycoplasma genitalium has been identified as a sexually transmitted pathogen only recently. Thus, less evidence is available to evaluate the effects of Mycoplasma genitalium infections in pregnancy.

In the current systematic review and meta-analysis, scientists have assessed the association between Mycoplasma genitalium infection and adverse pregnancy outcomes, including preterm birth, spontaneous abortion, premature rupture of membranes, low birth weight, and perinatal death.

Study design

Observational studies reporting the impact of Mycoplasma genitalium infection during pregnancy and in the immediate postpartum period were included in this systematic review. Various medical science databases were searched for the screening of studies. This led to the identification of a total of 116 studies.

Of identified studies, ten were included in the systematic review. Adverse pregnancy outcomes reported by two or more studies were included in the meta-analysis. Random-effects models were used for the meta-analysis.

Important observations

Among included studies, seven were conducted in high-income countries, and three were in low or middle-income countries. All studies had investigated one or more other sexually transmitted infections or genital infections along with Mycoplasma genitalium infection.

Preterm birth

A total of seven studies reported on Mycoplasma genitalium infection and preterm birth. Multiple confounding factors were addressed and adjusted in these studies, including maternal age, smoking habit, second-trimester bleeding, twin gestation, and previous preterm birth.

The meta-analysis of these studies revealed that Mycoplasma genitalium infection could significantly increase the risk of preterm birth.

Spontaneous abortion

 A total of six studies reported on Mycoplasma genitalium infection and spontaneous abortion. Only one study addressed some confounding factors, including maternal age, previous incidence of spontaneous abortion, smoking, and gestational age.

The meta-analysis of these studies could not find any significant association between Mycoplasma genitalium infection and spontaneous abortion.

Premature membrane rupture and low birth weight

Only one study from Japan and another from the US reported a univariable association between Mycoplasma genitalium infection and premature rupture of membranes and low birth weight, respectively.

Perinatal death

A univariable association between Mycoplasma genitalium infection and perinatal death was reported by two studies. The estimates reported by these studies were highly heterogeneous and, thus, could not be combined.

Study significance

This systematic review and meta-analysis have identified an association between Mycoplasma genitalium infection and preterm birth. However, no risk of spontaneous abortion has been observed in pregnant women with Mycoplasma genitalium infection.

Because of inadequate evidence, the causal association between Mycoplasma genitalium infection and preterm birth and other adverse pregnancy outcomes could not be determined. The scientists highlight the need for future studies of this kind to indicate routine testing and treatment of asymptomatic Mycoplasma genitalium infection in pregnancy.

Future studies should be designed prospectively and include multivariable analyses adjusting for potential confounding factors. Randomized controlled trials are also needed to understand whether testing and treatment of Mycoplasma genitalium infection during pregnancy reduce the risk of preterm birth and other complications.