Intrauterine haematomas in a recurrent miscarriage population

C.L. Tower,1 and L. Regan

Department of Reproductive Science and Medicine, Imperial College School of Medicine at St Mary's Hospital, Mint Wing, South Wharf Road, London W2 INY, UK


    Abstract
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 Acknowledgements
 References
 
BACKGROUND: This study examines the effect of intrauterine haematomas (IUH) discovered during early pregnancy ultrasound scanning in patients with recurrent miscarriage. Previous studies of IUHs have reported conflicting findings, and none studied women with recurrent miscarriage. METHODS: A total of 341 women with a viable pregnancy was included. Women with an IUH (n = 41) were compared with those without (n = 300). RESULTS: An IUH was identified by ultrasound in 12% (41/341) women. There were no differences in the number of live births between the two groups (25/41, 61% in the IUH group compared with 169/300, 56% without an IUH) or the number of miscarriages (6/41, 15% with an IUH compared with 72/300, 24% without an IUH). Anti-phospholipid antibodies were more common in the IUH group (21/31, 68% compared with 103/244, 42% P < 0.01). More women with haematomas experienced vaginal bleeding (16/31, 52% compared with 47/244, 19%, P < 0.01). These associations did not affect pregnancy outcome. Also, no increase in the rate of pregnancy complications was observed in the IUH group. CONCLUSIONS: The presence of an IUH in this potentially high risk patient group does not have a deleterious effect on pregnancy outcome.

Key words: intrauterine haematoma/pregnancy/recurrent miscarriage/ultrasound


    Introduction
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 Acknowledgements
 References
 
Recurrent miscarriage affects 1% of all women (Stirrat, 1990Go) and requires specialist investigation and treatment. All women referred to the dedicated Recurrent Miscarriage Clinic at St Mary's Hospital, London are investigated and treated according to our published protocol (Rai et al.1997Go). This clinic is a national referral centre. Recurrent miscarriage is defined by the clinic as three consecutive first trimester losses, but women with one or more late losses are also seen. Those women positive for anti-phospholipid antibodies receive treatment with low dose aspirin and heparin (Rai et al.1997Go). Supportive care is offered to all women, regardless of diagnosis, in their next pregnancy. Supportive care, or tender loving care as it otherwise known, involves regular ultrasound scans and review by medical staff at 1–2 week intervals throughout the first trimester. This is associated with an improved outcome (Stray-Pedersen and Stray-Pedersen, 1984Go; Liddell et al.1991Go; Clifford et al., 1997Go). These studies, although not randomized, have consistently shown that women receiving supportive care during the first trimester have a 72–86% chance of a successful pregnancy without pharmacological intervention. The mode of action has not been established although it has been suggested that stress may have an effect on uterine blood flow (Liddell et al.1991Go).

A intrauterine haematoma (IUH) is a crescent-shaped echo-free area between the membranes and the uterine wall (Mantoni and Pedersen, 1981Go). IUHs, in the presence of a viable fetus, are occasionally reported as an incidental finding on ultrasound scans performed during supportive care and then reported to the clinicians. The significance of these haematomas is not clear. IUHs have previously been described in the literature in women presenting with threatened miscarriage. Some reports have suggested that they increase the risk of spontaneous miscarriage (Jouppila, 1985Go; Borlum et al.1989Go), the risk of intrauterine growth restriction (Mandruzzato et al.1989Go) and preterm delivery (Borlum et al.1989Go). However, other reports have refuted these findings (Stabile et al.1989Go; Pedersen and Mantoni, 1990Go). To our knowledge, the clinical significance of IUHs has not been assessed in a population of women suffering recurrent miscarriage.

The aim of this study was to establish the incidence and clinical significance of IUHs in the presence of a viable fetus in a recurrent miscarriage population.


    Materials and methods
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 Acknowledgements
 References
 
All patients attending the early pregnancy clinic (a dedicated clinic for the care of patients with recurrent miscarriage) between January 1998 and August 1999 were identified in the clinic database. The medical notes for each patient were examined and information about each sequential ultrasound scan and pregnancy details documented. Only pregnancies with a crown–rump length >=6 weeks gestation with fetal heart activity present were included. All scans were performed by trained ultrasonographers using an Ultramark 9 scanner (Advanced Technology Laboratories, Bothel, Seattle, USA).

The following information was recorded: age; history of previous miscarriages; presence of anti-phospholipid antibodies (Rai et al.1997Go); presence of an IUH; occurrence of vaginal bleeding; number of early pregnancy scans and pregnancy outcome. The patients were then divided into two groups according to the presence or absence of an IUH and the two groups compared. Mann–Whitney U- and {chi}2-tests were used to statistically compare the groups. P values <0.05 were considered significant.


    Results
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 Acknowledgements
 References
 
A total of 341 patients with viable pregnancies (fetal heart seen) was identified. An IUH was reported in 41 (12%).

Table IGo shows there was no difference between the two groups in terms of age and number of previous miscarriages (P = not significant, Mann–Whitney U-test), or in the types of previous miscarriage (P = not significant, {chi}2-test).


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Table I. Age and previous miscarriage history
 
An IUH was detected at a median of 7 weeks (interquartile range 6–8.5 weeks) and resolved spontaneously before the end of the first trimester in most cases (median 11 weeks, interquartile range 7–15 weeks). Data on the size or location of the IUH was not collected.

Table IIGo demonstrates that women with an IUH were scanned more frequently during the first trimester than those without an IUH. All women were first scanned at a median of 6 weeks gestation, although the interquartile range for women with an IUH was 5–6 weeks and for those without was 6–7 weeks. This was a statistically significant difference (P < 0.01, Mann–Whitney U-test).


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Table II. Gestation and number of ultrasound scans
 
Table IIIGo shows that the presence of an IUH did not affect the miscarriage or live birth rate in this group of women. Unfortunately, some women were lost to follow up after the first trimester (when care is transferred to antenatal clinics, often at different centres). Although a similar number were lost to follow up in each group they have been excluded from subsequent analysis, leaving 31 women with an IUH and 244 women without. There was no difference in the median gestation at delivery; women with an IUH delivered at 39 weeks (interquartile range 36.5–40 weeks), those without also delivered at 39 weeks (interquartile range 38–40 weeks). Also, no difference in birth weight was observed between the two groups; birth weight for the IUH group was 3.25 kg (interquartile range 2.56–3.66 kg) and 3.39 kg (interquartile range 3.0–3.71 kg) for the group without.


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Table III. Pregnancy outcome
 
Table IVGo shows that women with an IUH were more likely to experience vaginal bleeding and were more likely to be positive for anti-phospholipid antibodies (P < 0.01, {chi}2). However, neither vaginal bleeding nor anti-phospholipid antibodies in women with a first trimester IUH affected pregnancy outcome.


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Table IV. Pregnancy outcome and complications
 
Table IVGo also shows no differences in pregnancy complications between the two groups. There was a possible trend towards preterm delivery at <32 weeks gestation in the IUH group but this did not reach statistical significance (P = 0.1376, {chi}2 with Yates correction).


    Discussion
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 Acknowledgements
 References
 
The finding of an IUH on first trimester ultrasound scan in patients with a history of recurrent miscarriage is common, occurring in 12% of pregnancies. A haematoma is associated with an increased risk of vaginal bleeding and it is reassuring to observe that the presence of vaginal bleeding did not affect pregnancy outcome. However, almost half of the women (48%) did not experience vaginal bleeding, indicating that many haematomas resolve spontaneously.

Women with an IUH were more likely to be positive for anti-phospholipid antibodies. These patients receive thromboprophylaxis, according to our previously published protocol (Rai et al.1997Go), of aspirin from the time of a positive pregnancy test and heparin from the time of demonstration of an intrauterine pregnancy. This may contribute to the more frequent finding of a haematoma in these patients. However, this association had no effect on pregnancy outcome.

It is perhaps not surprising to find that women with haematomas are scanned more frequently during their supportive care, as the presence of a possible `abnormality' provokes anxiety in both patients and clinicians. In the light of the findings of this study, these extra scans are of doubtful clinical benefit. Both groups of patients received their first and last ultrasound scans at the same median gestation. However, statistically (see interquartile ranges), the IUH group were first scanned at a marginally earlier gestation. However, this statistical difference is unlikely to have contributed to the total number of scans performed during the first trimester.

The presence of an IUH in this group did not increase the risk of pregnancy loss at any gestation. This agrees with two previous studies (Stabile et al.1989Go; Pedersen and Mantoni, 1990Go). However, unlike our study, these studies considered women presenting with threatened miscarriage so do not represent a similar group to ours. We also found no increased risk of pregnancy complications and no difference between the two groups in the number of live births. There was a possible trend towards preterm delivery at <32 weeks gestation in the haematoma group, which did not reach statistical significance (2/25 with an IUH, 2/169 without an IUH, P = 0.137, {chi}2 with Yates correction). Larger numbers are required to increase the power of the study to assess this aspect further. An increased risk of preterm labour was previously described, but only in patients with haematomas presenting in the second trimester (Borlum et al.1989Go). It has been suggested that the presence of blood within the uterus causes irritation and therefore stimulates contractions. However, in our study the haematomas disappeared spontaneously long before delivery, mostly by the end of the first trimester.

The data for this study were collected retrospectively so may be prone to bias. A larger prospective study is required to confirm the findings. Assessment of size and site of the lesion would be an interesting addition to such a study.

The ultrasound appearance of an IUH was first described almost 20 years ago in patients scanned between 11–20 weeks gestation (Mantoni and Pedersen, 1981Go). It has been assumed to represent blood but there is no concrete evidence that this is the case. However, whatever this ultrasound appearance represents we can conclude that in this population it is not a poor prognostic factor for pregnancy outcome. As a result of this study we can now confidently offer reassurance to these women.


    Acknowledgements
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 Acknowledgements
 References
 
We would like to thank all the staff at the Recurrent Miscarriage Clinic at St Mary's Hospital, Paddington, particularly Tracy McGrath, Clinic Co-ordinator, for her help in locating medical notes. We also acknowledge all the patients who participated in the study.


    Notes
 
1 To whom correspondence should be addressed. E-mail: c.tower{at}btinternet.com Back


    References
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 Acknowledgements
 References
 
Borlum, K.G., Thomsen, A, Clausen, I. et al. (1989) Long-term prognosis of pregnancies in women with intrauterine hematomas. Obstet. Gynecol., 74, 231–233.[Abstract]

Clifford, K., Rai, R. and Regan, R. (1997) Future pregnancy outcome in unexplained recurrent first trimester miscarriage. Hum. Reprod., 12, 387–389.[Abstract]

Jouppila, P. (1985) Clinical consequences after ultrasonic diagnosis of intrauterine hematoma in threatened abortion. J. Clin. Ultrasound, 13, 107–111.[ISI][Medline]

Liddell, H.S., Pattison, N. S. and Zanderigo, A. (1991) Recurrent miscarriageoutcome after supportive care in early pregnancy. Aust. N.Z. J. Obstet. Gynaecol., 31, 320–322.[ISI][Medline]

Mantoni, M. and Pedersen, J.F. (1981) Intrauterine haematoma. An ultrasonic study of threatened abortion. Br. J. Obstet. Gynaecol., 88, 47–51.[ISI][Medline]

Mandruzzato, G.P., D'Ottavio, G., Rustico, M.A. et al. (1989) The intrauterine hematoma: diagnostic and clinical aspects. J. Clin. Ultrasound, 17, 503–510.[ISI][Medline]

Pedersen, J.F. and Mantoni, M. (1990) Large intrauterine haematomata in threatened miscarriage. Frequency and clinical consequences. Br. J. Obstet. Gynaecol., 97, 75–77.[ISI][Medline]

Rai, R., Cohen, H., Dave, M. et al. (1997) Randomised controlled trial of aspirin and aspirin plus heparin in pregnant women with recurrent miscarriage associated with phospholipid antibodies. Brit. Med. J., 314, 253–257.[Abstract/Free Full Text]

Stabile, I., Campbell, S. and Grudzinskas, J.G. (1989) Threatened miscarriage and intrauterine hematomas. Sonographic and biochemical studies. J. Ultraound. Med., 8, 289–292.

Stirrat, G.M. (1990) Recurrent miscarriage I: Definition and epidemiology. Lancet, 336, 673–675.[ISI][Medline]

Stray-Pedersen, B. and Stray-Pedersen, S. (1984) Etiologic factors and subsequent reproductive performance in 195 couples with a prior history of habitual abortion. Am. J. Obstet. Gynecol., 148, 140–146[ISI][Medline]

Submitted on February 16, 2001; accepted on June 5, 2001.