Women who are pregnant and have mechanical prosthetic heart valves (MPHV) pose a major therapeutic dilemma for clinicians responsible for providing care. Two issues seem clear. Pregnancy in women with MPHV is very uncommon in the UK-the UKOSS study reports an occurrence in 0.0037% of pregnancies-one case in every 27 000 maternities, so very few UK practitioners will have direct experience in caring for these women. Pregnancy is a hypercoagulable state and women with MPHV require therapeutic dose anticoagulation throughout pregnancy to reduce the risk of valve thrombosis and its complications. A highly contentious issue is what constitutes the 'optimal' anticoagulant regi-men. Some clinicians (Regitz-Zagrosek et al. Eur Heart J 2011;32:3147-97) strongly favour continuing vitamin K antagonists, such as warfarin, throughout pregnancy, arguing that they are the most effective, albeit not 100% effective, at preventing thromboem-bolic complications (TEC). However, these drugs freely cross the placenta and are teratogenic. Warfarin embry-opathy is reported in up to 12% of infants exposed in the first trimester. Warfarin fetopathy (fetal loss, stillbirth and neurological problems) is reported in up to 25% women exposed to war-farin in later pregnancy. Much has been made of a 'safe' warfarin dose but there is no dose that prevents adverse fetal outcomes (McLintock Best Pract Res Clin Obstet Gynecol 2014;28:519-36). This has prompted the demand for alternative approaches to anticoag-ulation. Low-molecular-weight heparin (LMWH) does not cross the placenta, is not teratogenic and its use is associated with live birth rates of 95% in women with MPHV. Although it is not as effective at preventing TEC, the best outcomes are achieved if women are able to comply with twice daily injections of LMWH and have regular anti-Xa levels to guide dose adjustments as pregnancy progresses. Critical to the clinical efficacy of LMWH is ensuring adequate levels of anticoagu-lation. Peak anti-Xa levels will predict the maximum anticoagulant effect of LMWH and risk of bleeding. Trough levels ensure that anticoagulation is within a therapeutic threshold. Whether targeting peak and trough levels is associated with lower risks of TEC has not been tested in a large prospective study. The UKOSS study highlights an inconsistent and inadequate approach to anticoagulant management. Practitioners did not seem to appreciate the complexities inherent in providing safe anticoagulation or the high risk of these pregnancies. One in five women were not referred for specialist care at any stage during their pregnancy. Of the women who chose 'therapeutic dose' LMWH throughout pregnancy, data on anti-Xa monitoring was available in just over half, with alarming variations in the frequency and timing of testing, and target anti-Xa levels. Inappropriate LMWH dosing and poor compliance were associated with poor maternal outcome. Given the inadequacies in clinical care, it is not surprising that clinical outcomes in the cohort overall were poor and it is uncertain if...

To describe the incidence of mechanical prosthetic heart valves (MPHV) in pregnancy in the UK; rates of maternal and fetal complications in this group of women, and whether these vary with the anticoagulation used during pregnancy. Design Prospective descriptive population based study SettingAll consultant-led maternity units in the UK PopulationAll women with a MPHV who were pregnant between 1 st February 2013 and 31 st January 2015 MethodsCollection and analysis of anonymous data relating to pregnancy management and outcome, using the UKOSS notification and data collection system Main Outcome MeasuresMaternal death, serious maternal morbidity, poor fetal outcome ResultsData were obtained on 58 women giving an estimated incidence of 3.7 (95% CI 2.7-4.7) per 100,000 maternities. There were 5 maternal deaths (9%); a further 24 (41%) suffered serious maternal morbidity. There was a poor fetal outcome from 26 (47%) pregnancies. Only 16 (28%) women had a good maternal and good fetal outcome. Low Molecular Weight Heparin (LMWH) 4 was used throughout pregnancy by 71% of women. Of these 83% required rapid dose escalation in the first trimester. Monitoring regimes lacked consistency. ConclusionsThis study has estimated the incidence of MPHV in pregnant women in the UK. It includes the largest cohort managed with LMWH throughout pregnancy reported to date. It demonstrates a high rate of maternal death, serious maternal and fetal morbidity.Women with MPHVs, and their clinicians need to appreciate the significant maternal and fetal risks involved in pregnancy. Care should be concentrated in specialist centres.

Background Instrumental delivery accounts for approximately 10-15% of UK deliveries. It is increasingly scrutinised for complication rates, yet there is variable data in the literature describing complication rates in the UK, with, for example, third degree tear rates for forceps deliveries of 8-12% being reported (RCOG 2010). This study sought to describe complication rates in a large UK cohort, which could subsequently be used to generate audit standards. Methods Data was collected from all instrumental deliveries conducted at a large tertiary referral centre from October 2008- June 2011, using an electronic audit proforma that also served as the medical record. Results Data was available for 1985 deliveries; 688 (35%) ventouse, 905 (46%) forceps, 178 (9%) kiellands, 51 (2%) rotational ventouse, 163 (8%) 2 instruments. Forceps was associated with an increased risk of third degree tears (p<0.01 Mann-Whitney) of 6.3% compared to 2.6% for ventouse delivery. Forceps were also associated with an increased estimated blood loss (EBL) of median 500mls (interquartile range 300-700mls) compared to 300mls (200-500mls) for ventouse (p<0.01). Babies born using forceps had a higher median birthweight of 3452g (IQR 3100-3835) compared to 3250g (IQR 2948-3600g) for ventouse, (p<0.01, Mann-whitney). Conclusions This cohort represents one of the largest published UK cohorts of women undergoing instrumental deliveries, and can be used to set audit standards. Forceps is associated with increased blood loss and third degree perineal trauma. However, the risks of the latter were less than those suggested in the RCOG consent advice, suggesting this guidance may require adjustment.

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