A Matter of Timing-Pregnancy After Bariatric Surgery.

PURPOSE: Current guidelines recommend to avoid pregnancy for 12-24 months after bariatric surgery because of active weight loss and an increased risk of nutritional deficiencies. However, high-quality evidence is lacking, and only a few studies included data on gestational weight gain. We therefore evaluated pregnancy and neonatal outcomes by both surgery-to-conception interval and gestational weight gain. MATERIALS AND METHODS: A multicenter retrospective analysis of 196 singleton pregnancies following Roux-en-Y gastric bypass, sleeve gastrectomy, and one anastomosis gastric bypass was conducted. Pregnancies were divided into the early group (≤ 12 months), the middle group (12-24 months), and the late group (> 24 months) according to the surgery-to-conception interval. Gestational weight gain was classified as inadequate, adequate, or excessive according to the National Academy of Medicine recommendations. RESULTS: Pregnancy in the early group (23.5%) was associated with lower gestational age at delivery (267.1 ± 19.9 days vs 272.7 ± 9.2 and 273.1 ± 13.5 days, P = 0.029), lower gestational weight gain (- 0.9 ± 11.0 kg vs + 10.2 ± 5.6 and + 10.0 ± 6.4 kg, P < 0.001), and lower neonatal birth weight (2979 ± 470 g vs 3161 ± 481 and 3211 ± 465 g, P = 0.008) than pregnancy in the middle and late group. Inadequate gestational weight gain (40.6%) was associated with lower gestational age at delivery (266.5 ± 20.2 days vs 273.8 ± 8.4 days, P = 0.002) and lower neonatal birth weight (3061 ± 511 g vs 3217 ± 479 g, P = 0.053) compared to adequate weight gain. Preterm births were also more frequently observed in this group (15.9% vs 6.0%, P = 0.037). CONCLUSION: Our findings support the recommendation to avoid pregnancy for 12 months after bariatric surgery. Specific attention is needed on achieving adequate gestational weight gain.

Differentiating between gestational and chronic hypertension; an explorative study.

OBJECTIVE: Guidelines define hypertension diagnosed before 20 weeks' gestation as chronic hypertension (CH) and thereafter as gestational hypertension (GH). We tested whether hypertension diagnosed before 20 weeks is preceded by CH and whether pregnancy outcome depends on the time of onset of hypertension. DESIGN: Retrospective cohort study. SETTING: Tertiary obstetric center. POPULATION: Women with a history of obstetric vascular complications. METHODS: Blood pressure data prior to and during pregnancy and subsequent maternal and neonatal outcome were reviewed in 148 women. Women were grouped according to the onset of hypertension; pre-pregnancy (CH), before 20 weeks' (early GH), after 20 weeks' gestation (late GH) and normotensive. MAIN OUTCOME MEASURES: Onset of hypertension, obstetric complications (pre-eclampsia, HELLP (hemolysis, elevated liver enzymes and low platelets) syndrome, intra-uterine growth restriction). RESULTS: Twenty-nine women had CH. Early GH occurred in 46 women and another 32 developed late GH. Of 75 women with hypertension in the first half of pregnancy, 29 (39%) had CH and 46 (61%) early GH. Obstetric complications occurred more often in all hypertensive women, but no differences between the CH and GH groups could be detected. CONCLUSIONS: Hypertension detected in the first half of pregnancy does not necessarily indicate chronic hypertension. Hypertension in general is related to hypertensive maternal complications and fetal growth restriction. Differentiating between chronic or gestational hypertension does not seem to help in establishing the risk for later hypertensive sequelae or intra-uterine growth restriction.

Exercise-induced changes in venous vascular function in nonpregnant formerly preeclamptic women.

OBJECTIVE: Formerly preeclamptic women with low plasma volume are at increased risk of recurrent gestational hypertensive disease. We hypothesized that a 4-week cycling training in formerly preeclamptic women improves (venous) hemodynamic function. METHODS: In 9 formerly preeclamptic women, we examined physical fitness and hemodynamic function, before and after the training. We assessed blood pressure, heart rate, cardiac output, plasma volume, and calf and forearm venous compliance. RESULTS: After the training, baseline blood pressure and cardiac output remained unchanged, but resting heart rate decreased (-7%, P = .02). Plasma volume was 8% higher after training (P = .01). Calf venous compliance increased (+18%, P = .02) but not forearm venous compliance (+14%, P = .09). CONCLUSION: Cycling training improves venous vascular function in formerly preeclamptic women. The decreased resting heart rate and improvement of venous compliance suggest reduced sympathetic activity. These rapid exercise-induced changes may improve maternal vascular adaptation in early pregnancy and with it the risk of (recurrent) gestational hypertensive disease.

Blunted autonomic response to volume expansion in formerly preeclamptic women with low plasma volume.

OBJECTIVE: We hypothesize that low plasma volume in normotensive formerly preeclamptic women reflects reduced venous storage capacity. To test this hypothesis, we compared circulatory and autonomic responses to acute volume loading between women with low and those with normal plasma volume. METHODS: In 24 normotensive formerly preeclamptic women at least 6 months postpartum, we administered 500 mL of iso-oncotic fluid by constant intravenous infusion in 30 minutes, while recording changes in heart rate, blood pressure, cardiac output, and measuring active plasma renin and alpha-atrial natriuretic peptide concentrations. We estimated arterial sympathetic control, cardiac autonomic regulatory balance, and baroreflex sensitivity using spectral analysis. Intergroup and intragroup changes were analyzed nonparametrically. RESULTS: 17 women (71%) had low plasma volume and 7 (29%) had normal plasma volume. Plasma volume expansion induced comparable changes in blood pressure, heart rate, baroreflex sensitivity, and active plasma renin concentration in low plasma volume and normal plasma volume. Cardiac output and alpha-atrial natriuretic peptide increased in low plasma volume but not in normal plasma volume. Volume expansion reduced sympathetic activity ( from 2.41 to 1.76 mm Hg(2), P = .03) in normal plasma volume but not in low plasma volume ( from 2.72 to 2.48 mm Hg(2), P > .05). CONCLUSION: The sympathoinhibitory response to volume expansion is diminished in low plasma volume, which suggests that cardiovascular reflex function is impaired. We speculate that this defect contributes to circulatory maladaptation to pregnancy, sympathetic dominance, and the development of gestational hypertensive disease.

Venous response to orthostatic stress.

Head-up tilt (HUT) induces a reduction in preload, which is thought to be restored through sympathetic venoconstriction, reducing unstressed volume (V(u)) and venous compliance (VeC). In this study, we assessed venous inflow and outflow responses and their reproducibility and determined the relation with autonomic function during HUT. Eight healthy non-pregnant women were subjected to 20 degrees head-down tilt to 60 degrees HUT at 20 degrees intervals. At each rotational step, we randomly assessed forearm pressure-volume (P-V) curves (venous occlusion plethysmography) during inflow (VeC(IN)) and outflow [venous emptying rate (VER(OUT))]. VeC(IN) was defined as the ratio of the slope of the volume-time curve and pressure-time curve, with direct intravenous pressure measurement. VER(OUT) was determined using the derivate of a quadratic regression model using cuff pressure. We defined V(u) as the y-intercept of the P-V curve. We calculated, for both methods, the coefficients of reproducibility (CR) and variation (CV). Vascular sympathetic activity was determined by spectral analysis. VeC(IN) decreased at each rotational step compared with the supine position (P<0.05), whereas VER(OUT) increased. CR of VeC(IN) was higher in the supine position than VER(OUT) but lower during HUT. CV varied between 19% and 25% (VeC(IN)) and between 12% and 21% (VER(OUT)). HUT decreased V(u). The change in VeC(IN) and VER(OUT) correlated with the change in vascular sympathetic activity (r= -0.36, P<0.01, and r=0.48, P<0.01). This is the first study in which a reproducible reduction in VeC(IN) and V(u) and a rise in VER(OUT) during HUT are documented. The alterations in venous characteristics relate to changes in vascular sympathetic activity.

The relation between venous reserve capacity and low plasma volume.

OBJECTIVE: Prepregnant low plasma volume (LPV) is associated with subsequent gestational hypertensive disease. It is unknown to what extent an LPV affects the venous reserve capacity (VRC). We tested the hypothesis that LPV reduces the VRC, as indicated by presyncope or altered cardiovascular changes in response to head-up tilt. STUDY DESIGN: In 52 nonpregnant women with a history of preeclampsia or recurrent miscarriage, the authors assessed plasma volume, stroke volume, and cardiac output and determined blood pressure, heart rate, and autonomic responses to stepwise inflicted head-up tilt. RESULTS: 12 participants had LPV, which related to presyncope when compared with subjects with normal plasma volume (NPV). Women with LPV without presyncope demonstrated a circulatory response comparable to NPV women at the expense of consistently higher heart rate. CONCLUSION: LPV decreases the capacity to cope with head-up tilt without affecting the response pattern, suggesting reduced VRC.

Thrombophilias and recurrent pregnancy loss: a critical appraisal of the literature.

Thrombophilias are suggested to play a role in recurrent miscarriage. The aim of this study was to evaluate the literature of the past 10 years regarding the association between thrombophilias and recurrent miscarriage. We concluded that there is a large variety in applied study methodology. Therefore, we defined criteria for an adequate study on the relationship of thrombophilias on recurrent pregnancy loss: (i) no exclusion criteria for patients or at least the same criteria for patients and controls; (ii) a clear definition of the gestational age at previous losses; (iii) a well-described control group; (iv) clear description of the test methods and moment of testing; and (v) a clear description of the (non) significant differences or odds ratio between cases and controls. Eleven out of 69 studies fulfilled these criteria. Their results show significant higher serum homocysteine levels among women with a history of recurrent miscarriage. No relation was found between recurrent miscarriage and the methylenetetrahydrofolate reductase C667T mutation. No relation was observed for the levels of antithrombin, protein C and protein S. Seven studies on the association of factor V Leiden (FVL) and/or pathologic activated protein C ratio (pAPCR) showed that FVL may play a role in second trimester losses, as do antiphospholipid antibodies. Studies on the prothrombin gene mutation yielded conflicting results. Consequently, large prospective studies according to the aforementioned criteria are needed to establish if there is a relationship between thrombophilias and recurrent miscarriage at all. At present, there is only justification for testing for homocysteine levels, antiphospholipid antibodies and FVL in women with a history of recurrent miscarriage.

Pregnancy outcome in patients with a history of recurrent spontaneous miscarriages and documented thrombophilias.

The aim of this study was to evaluate the effect of treatment in patients analyzed for recurrent spontaneous miscarriage with a diagnosis of a hereditary thrombophilia, the presence of antiphospholipid and/or autoimmune antibodies, and/or hyperhomocystinemia (HHC) with or without methylenetetrahydrofolate reductase (MTHFR) polymorphisms. In total, 76 women with 2 or more embryonic or fetal losses were analyzed. Of these, 49 (64.4%) women were found to have one or more thrombophilias and/or autoimmune antibodies, and 33 (43.4%) women were found to have a MTHFR polymorphism and/or HHC. Since completion of the recurrent miscarriage analysis, 39 women conceived again. All women with a thrombophilia were treated with low-dose aspirin plus low molecular weight heparin. All women with previously diagnosed HHC and/or MTHFR polymorphisms were treated with folate and vitamin B(6) and B(12) supplementation. In the thrombophilia group, 27 women conceived resulting in 20 successful pregnancies (74.1%) and 7 pregnancy losses (2 trisomy 16, 1 ectopic pregnancy and 4 unexplained miscarriages), i.e. an unexplained pregnancy loss rate of 14.8%. In the HHC/MTHFR group 22 women conceived, resulting in 17 successful pregnancies (77.3%) and 5 pregnancy losses (1 trisomy 16, 1 Turner syndrome and 3 unexplained miscarriages), i.e. an unexplained pregnancy loss rate of 13.6%.