Obstetrical complications in women suffering from concomitant adenomyosis: a single center retrospective cohort

Background
The objective of this study was to characterize the population of pregnant women diagnosed with adenomyosis with potentially related obstetrical complications in our tertiary center.

Methods
A retrospective single center study was conducted on women who delivered in the OBGYN Department at Citadelle Hospital-CHU Liège. Clinical data were collected from the medical reports and the electronic patient data files.

The first inclusion criteria was the availability of imaging prior to the selected singleton pregnancy or during the postpartum describing the uterus and identifying signs of adenomyosis (if applicable). From this pool, all the women with complicated pregnancies or deliveries were selected and then matched with women with an uncomplicated pregnancy and delivery occurring on the same day. Complications of interest were late miscarriage, prematurity (early and late), small for gestational age, intrauterine growth retardation, gestational hypertension, pre-eclampsia, HELLP syndrome, stillbirth, placenta praevia, placenta accreta spectrum and postpartum hemorrhage.

Results
From 1st January 2020 to 31st December 2023, 9696 women delivered in our maternity ward, from which we identified a total of 2620 cases based on our first inclusion criteria. The cohort consisted of mostly Caucasian women (79%), the conception was in 88.9% spontaneous, and the mean age at delivery was 30.7 years (range: 14 – 49 years) with a predominance for vaginal delivery (70.4%). The total rate of adenomyosis was 3.3% (86 women).

With the aim of determining the impact of adenomyosis on pregnancy, we first compared the group with adenomyosis (n =86) with the group without adenomyosis (n= 2534). We observed that women diagnosed with adenomyosis were older (34.0 years vs 30.6 years, p <0.001), delivered 9 days earlier (gestational age in days: 258.8 vs 267.5, p < 0.05), and their estimated blood loss during the delivery was higher (456.2 ml vs 384.9 ml, p<0.05). Moreover, the overall rate of complication observed in the adenomyosis group was higher (63.9%) in comparison to the group without adenomyosis (49.2%) (p<0.01, OR 1.8).

When focusing only on the group with complications (1302 cases including 55 with adenomyosis), we observed significant higher rates of late miscarriages (10.9% vs 3.8%, p<0.05, OR 3.05) and placenta praevia (7.3% vs 2.1%, p<0.05, OR 3.68) in the subgroup presenting adenomyosis. For other pregnancy and delivery complications such as described above, no statistically significant difference related to adenomyosis was observed.

Conclusions
In this cohort, pregnant women with adenomyosis are at a higher risk for earlier delivery and higher estimated blood loss at delivery. Moreover, special attention must be taken within this group regarding late miscarriage and placenta praevia as their rates are increased.