Associations between first-trimester intrauterine hematoma and twin pregnancy outcomes: a retrospective cohort study

Pregnancy outcomes of fetal reduction in patients with intrauterine haematoma following double embryo transfer

RESEARCH QUESTION

Is there an association between intrauterine haematoma (IUH) and pregnancy outcomes in patients who undergo fetal reduction after double embryo transfer (DET), and if so, what is the relationship between IUH-related characteristics and pregnancy outcomes?

DESIGN

Clinical information and pregnancy outcomes of women who underwent fetal reduction after DET were analysed. Patients with other systematic diseases, ectopic pregnancy or heterotopic pregnancy, monochorionic twin pregnancies and incomplete data were excluded. Stratification of IUH pregnancies was undertaken based on IUH-related characteristics. The main outcome was incidence of fetal demise (<24 weeks), with other adverse pregnancy outcomes considered as secondary outcomes.

RESULTS

Thirty-four IUH patients and 136 non-IUH patients who underwent fetal reduction after DET were included based on a 1:4 match for age, cycle type and fertilization method. IUH patients had a higher incidence of early fetal demise (20.6% versus 7.4%, P = 0.048), threatened abortion (48.1% versus 10.3%, P<0.001) and postpartum haemorrhage (PPH; 14.8% versus 4.0%, P = 0.043) compared with non-IUH patients. IUH was an independent risk factor for early fetal demise [adjusted OR (aOR) 3.34, 95% CI 1.14-9.77] and threatened abortion (aOR 8.61, 95% CI 3.28-22.61) after adjusting for potential confounders. IUH pregnancies undergoing fetal reduction that resulted in miscarriage had larger IUH volumes and earlier diagnosis (both P < 0.03). However, IUH characteristics (i.e. volume, changing pattern, presence or absence of cardiac activity) were not associated with threatened abortion or PPH.

CONCLUSIONS

Fetal reduction should be performed with caution in IUH pregnancies after DET as the risk of fetal demise is relatively high. Particular attention should be given to IUH patients with early signs of threatened abortion and inevitable fetal demise.

The risk factors and impact of subchorionic hematoma in the first trimester in IVF twin pregnancies: a prospective cohort study

Objective

This study aimed to identify the risk factors for subchorionic hematoma (SCH) in the first trimester of in vitro fertilization (IVF) twin pregnancies and investigate the impact of SCH on pregnancy outcomes.

Study design

A prospective cohort study was conducted at Chengdu Women and Children's Central Hospital. The study recruited patients who were identified with twin pregnancies in the first trimester, undergoing IVF treatment from January 2020 to May 2021. The demographic characteristics and pregnancy outcomes were compared between the SCH and the non-SCH groups. A logistic regression analysis was used to determine the risk factors for SCH and adverse pregnancy outcomes.

Results

In the first trimester, 38% of patients developed SCH. The independent risk factors for SCH included male factor, hydrosalpinx, polycystic ovary syndrome (PCOS), previous miscarriage, and adenomyosis. With respect to the pregnancy outcomes, only the rate of twin pregnancy loss before 20 gestational weeks was significantly higher in the SCH group than in the non-SCH group. After adjusting for the confounding factors, the presence of SCH diminished the ovarian reserve, and previous miscarriage was independently related to twin pregnancy loss before 20 gestational weeks.

Conclusion

This may be the first study to evaluate the risk factors of SCH in twin pregnancies who underwent IVF-ET/FET treatment, which may provide some theoretical basis for clinical practice in the future. Furthermore, it was found that the occurrence of SCH was associated with the loss of both pregnancies before 20 gestational weeks. Therefore, these patients should be offered increased surveillance and timely treatment.

Vanishing twin syndrome is associated with first-trimester intrauterine hematoma in twin pregnancies after in vitro fertilization

RESEARCH QUESTION

Is there an association between intrauterine hematoma (IUH), vanishing twin syndrome (VTS), and subsequent complications in twin pregnancies after in vitro fertilization (IVF)? What are the risk factors for these complications?

DESIGN

Women who presented with two live gestational sacs following double embryo transfer were included. Patients with systematic diseases, artificial fetal reduction, and incomplete data were excluded. Further stratification of IUH pregnancies was performed according to IUH-related characteristics (i.e., volume, changing pattern, and relationship with fetal cardiac activities). The primary outcome was the incidence of VTS, while adverse outcomes in the surviving singleton and the gestational age of VTS were secondary outcomes.

RESULTS

The incidence of IUH was 13.8%. A total of 1,078 twin pregnancies including 539 IUH pregnancies and 539 non-IUH pregnancies were included. IUH pregnancy was associated with higher risks of VTS (26.9% vs. 18.7%, p = 0.001) as well as a higher incidence of preterm birth (p = 0.001, crude OR = 1.98, 95% CI 1.28-3.09, adjusted OR = 1.19, 95% CI 1.09-1.24), threatened abortion (p < 0.001, crude OR = 9.12, 95% CI 2.90-28.69, adjusted OR = 6.63, 95% CI 1.69-14.67), and postpartum hemorrhage (p = 0.024, crude OR = 3.13, 95% CI 1.09-8.99, adjusted OR = 1.16, 95% CI 1.08-1.32) in the surviving singleton. There was no significant difference in risks of other complications. The absence of fetal cardiac activities at the diagnosis of IUH predicted VTS (p < 0.001, crude OR 4.67, 95% CI 3.67-5.78, adjusted OR 3.33, 95% CI 1.56-5.14) and fetal loss at smaller gestational age (7.81 ± 2.10 vs. 11.39 ± 5.60 weeks, p < 0.001), while an IUH with an increasing volume did not increase the risk of VTS but might induce threatened abortion in the surviving fetus (p < 0.001, crude OR 1.84, 95% CI 1.32-2.55, adjusted OR 1.72, 95% CI 1.13-2.13).

CONCLUSIONS

IUH was a risk factor for VTS in twin pregnancies following double embryo transfer and elevated the risks of threatened abortion, preterm birth, and postpartum hemorrhage in the surviving singleton. The absence of fetal cardiac activities at the diagnosis of IUH elevated the risks of VTS, while an IUH with an increasing volume was associated with threatened abortion without elevating the risks of VTS. An IUH diagnosed before the presence of fetal cardiac activities also resulted in an earlier miscarriage. The study suggests that attention be paid to twin pregnancies with first-trimester IUH to prevent VTS and subsequent adverse perinatal outcomes.

HIGHLIGHTS

First-trimester intrauterine hematoma (IUH) following double embryo transfer is associated with a higher incidence of vanishing twin syndrome (VTS) and elevated subsequent risk of threatened abortion, preterm birth, and postpartum hemorrhage in the surviving singleton. Other perinatal outcomes were not associated with the diagnosis of first-trimester IUH. The absence of fetal cardiac activities at the diagnosis of IUH was of predictive value toward VTS, while an IUH with an increasing size was associated with threatened abortion without elevating the risk of VTS. Incomplete fetal cardiac activities and earlier detection of an IUH might also predict miscarriage at smaller gestational age.