Timing of administration of antenatal magnesium sulfate and umbilical cord blood magnesium levels in preterm babies

Background: The optimum timing of administration of magnesium sulfate (MgSO₄) in relation to delivery is not known. The general consensus is to achieve administration to the mother at least 4?hours prior to preterm delivery.

Objective: To investigate potential predictors of umbilical cord blood magnesium (Mg) concentrations, in particular, timing of antenatal MgSO₄ administration in relation to delivery.

Study design: A prospective observational study of infants delivered at less than 32 weeks’ gestational age. Cord bloods samples were collected at delivery and Mg levels analyzed.

Results: Of the 81 included cases, five received no antenatal MgSO₄, 65 received a 4?g bolus only, and 11 received a 4?g bolus and 1?g/hour infusion. The median time of bolus administration before delivery was 104?minutes (IQR: 57–215). The mean magnesium level was 0.934?mmol/L in the no antenatal MgSO₄ group, 1.018?mmol/L in the bolus only group, and 1.225?mmol/L in the bolus and infusion group (p?Conclusions: In the bolus only group, the highest mean Mg levels were observed with administration 1–2?hours before delivery, but the findings were not statistically significant. Compared to the rest of the cohort, higher Mg levels were found when a bolus was followed by an infusion. Following a MgSO₄ bolus, some growth restricted extremely preterm babies may have higher Mg levels than would be otherwise expected.     

The effects of ritodrine and magnesium sulfate on maternal and fetal Doppler blood flow patterns in women with preterm labor

Objective

To determine the effects of ritodrine and magnesium sulfate on maternal-fetal blood flows.

Study design

A total of 85 pregnant women between 26th and 36th weeks with preterm labor, and 83 healthy pregnant women were included. Patients in the study group were randomly assigned to receive either ritodrine (with the addition of verapamil) (n = 46) or magnesium sulfate (n = 39). Blood flow examinations on the umbilical artery (UA), middle cerebral artery (MCA), bilateral uterine arteries (Ut.A) and ductus venosus (DV) were performed before and 48 h after initiating therapy.

Results

UA pulsatility index (PI) significantly differed in women receiving tocolysis compared to controls after 48 h. DV PI increased in women receiving MgSO₄, whereas it decreased in the ritodrine and control groups. Ut.A values did not significantly change after 48 h in the groups.In women between the 26th and 32nd weeks, UA, MCA and DV PI did not significantly change after 48 h in the three groups. However, in women between the 32nd and 36th weeks UA and MCA PI significantly differed in the treatment groups compared to controls after 48 h. DV PI increased in women receiving MgSO₄, whereas it decreased in the ritodrine and control groups.

Conclusions

MgSO₄ and ritodrine affect blood flow patterns after 48 h in some maternal-fetal vessels. These effects on blood flow are particularly significant in women between 32nd and 36th weeks. The effects of both drugs on fetal and maternal Doppler flows seem similar, except the increased resistance to flow in DV in women receiving MgSO₄.     

Contemporary management of preterm premature rupture of membranes (PPROM): a survey of maternal-fetal medicine providers

OBJECTIVE: This study was undertaken to characterize variations in the management for women with preterm premature rupture of membranes (PPROM) among maternal-fetal medicine (MFM) specialists in the context of current recommendations for clinical practice and evidenced-based practice. STUDY DESIGN: We performed a Web-based survey of 1375 MFM providers. Participants were queried on practice characteristics and management issues including use of tocolytics, antibiotics, steroids, and timing of delivery. RESULTS: A total of 508 providers (37%), representing all 50 states and 13 countries, responded to the survey. Only 30% reported a formal departmental protocol for managing women with PPROM. Consistent use of steroids (99.4%) and antibiotics (99.6%) were reported. Administration of steroids was confined to < or =32 weeks by 37%, and < or =34 weeks by 51% of practitioners. Repeated dosing of steroids was uncommon (16%). The antibiotics use and rationale for use varied among respondents. Tocolytics were used by 73% of respondents with magnesium sulfate the main agent used (98%). Use of tocolytics was generally used for 48 hours or less to attain steroid benefit (88%). Amniocentesis was used by 66% of practitioners in the acute evaluation of PPROM. Fetal lung maturity testing was reported by 78% with variability noted with respect to the test used. Outpatient management of women with PPROM after viability was noted by 43% of respondents. Gestational age at which expectant management is abandoned in women with PPROM varied significantly between respondents: > or =34 weeks by 56%, > pr =35 weeks by 26%, > or =36 weeks by 12%, and > or =37 weeks by 4.0%. CONCLUSION: Although many management practices for women with PPROM are consistent with currently available evidence and practice recommendations, substantial variations still exist among MFM providers.     

Antenatal magnesium sulfate is beneficial or harmful in very preterm and extremely preterm neonates: a new insight

Aims: To evaluate whether antenatal MgSO₄ is beneficial or harmful in very preterm and extremely preterm neonates.

Materials and methods: We retrieved published literature through searches of PubMed or Medline, CINAHL, and the Cochrane Library. Results were restricted to systematic reviews, meta-analysis, randomized controlled trials (RCTs), and relevant observational studies.

Results: Evidence revealed that antenatal MgSO₄ has neuroprotective role in preterm neonates and it decreased the risk of cerebral palsy and gross motor dysfunction. Evidences regarding association of antenatal MgSO₄ with feed intolerance, NEC and SIP were from cohort studies and controversial.

Conclusions: We should continue use antenatal MgSO₄ to all eligible patients according to protocol till the more robust evidence will suggest association with gastrointestinal complications. In the meantime, we should have a high index of suspicion of gastrointestinal complications in extremely preterms particularly <26 weeks of gestation.     

Homocysteine levels and its association with intraventricular hemorrhage in preterm infants born to preeclamptic mothers

Abstract

Objective: To investigate the relation between serum homocysteine levels and intraventricular hemorrhage (IVH) in preterm infants born to preeclamptic mothers.

Method: This study included 84 preterm infants (42 born to preeclamptic mothers and 42 born to normotensive healthy mothers) who were admitted to Izmir Tepecik Training and Research Hospital Neonatology Clinic on the postnatal first day. The measurement of homocysteine levels in all samples were performed with an Immulite 2000 analyzer, using the chemiluminescence method. Cranial ultrasounds were performed on the fourth day and in the 1 month of age.

Results: The mean plasma levels of homocysteine in infants born to preeclamptic mothers and in the control group were 8.2?±?5.9?μmol/L and 5.3?±?2.7?μmol/L, respectively. The plasma levels of homocysteine were significantly higher in the study group (p?=?0.006). There was no association between the plasma homocysteine levels and IVH or other neonatal complications including necrotizing enterocolitis, retinopathy of prematurity, bronchopulmonary dysplasia and mortality.

Conclusion: Our data suggest that plasma levels of homocysteine are higher among infants born to preeclamptic mothers, but these high levels are not associated with IVH and other neonatal complications in preterm infants.     

The natural history of preterm premature rupture of membranes in twin pregnancies

Objective: To compare the characteristics of preterm premature rupture of membranes (PPROM) between twin and singleton pregnancies.

Methods: This was a retrospective study of all women with twin and singleton pregnancies admitted with PPROM between 24–34 weeks of gestation.

Results: Overall 698 women with PPROM were eligible for the study: 101 (14.5%) twins and 597 (85.5%) singletons. Twins presented with PPROM at a more advanced gestational age compared with singletons (29.1?±?2.7 vs. 28.5?±?2.8 weeks, p?=?0.03). The latency period was shorter in twins compared with singletons, especially for women presenting after 28 weeks of gestation (5.0?±?0.8 vs. 7.0?±?0.4 days, p?=?0.01). Women with twins were more likely to deliver within 48?h (OR:?2.7; 95%CI: 1.7–4.2) and were less likely to deliver within 2–7 days (OR: 0.5; 95%CI: 0.3–0.9) following PPROM. The rate of clinical chorioamnionitis or placental abruption following PPROM was lower in twins compared with singletons (15.8% vs. 26.0%, p?=?0.03).

Conclusions: PPROM in twin pregnancies tends to occur at a more advanced gestational age, is associated with a shorter latency period and is less likely to be complicated by chorioamnionitis or placental abruption compared with singletons. This information may be useful for counseling and management decisions in cases of PPROM in women with twins.     

Trends in preterm birth in singleton deliveries in a Hong Kong population

Objective

To examine trends in preterm birth and its relationship with perinatal mortality in Hong Kong.

Methods

In a retrospective cohort study, data were reviewed from singletons delivered between 1995 and 2011 at a university teaching hospital. Trends in preterm birth (between 24 and 36 weeks of pregnancy), perinatal mortality, and subtypes of preterm birth (spontaneous, iatrogenic, and following preterm premature rupture of membranes [PPROM]) were examined via linear regression.

Results

There were 103 364 singleton deliveries, of which 6722 (6.5%) occurred preterm, including 1835 (1.8%) early preterm births (24–33 weeks) and 4887 (4.7%) late preterm births (34–36 weeks). Frequency of preterm birth remained fairly consistent over the study period, but that of spontaneous preterm birth decreased by 25% (β = –0.83; P < 0.001), from 4.5% to 3.8%. Frequency of preterm birth following PPROM increased by 135% (β = 0.82; P < 0.001), from 0.7% to 1.7%. The perinatal mortality rate decreased from 56.7 to 37.0 deaths per 1000 deliveries before 37 weeks (β = –0.16; P = 0.54). Early preterm birth contributed to 16.0% of all deaths.

Conclusion

Although the overall rate of preterm birth in Hong Kong has remained constant, the frequencies of its subtypes have changed. Overall perinatal mortality is gradually decreasing, but early preterm birth remains a major contributor.     

Oral nicardipine versus intravenous magnesium sulfate for the treatment of preterm labor

OBJECTIVE: The aim of this study was to compare the efficacy and safety of oral nicardipine in acute therapy for preterm labor with those of parenteral magnesium sulfate. STUDY DESIGN: Patients between 24 and 34 weeks' gestation with documented preterm labor were randomly assigned to receive oral nicardipine (n = 57) or intravenous magnesium sulfate (n = 65) as initial tocolytic therapy. Patients in the nicardipine group received a 40-mg loading dose and then 20 mg every 2 hours as needed to stop contractions (total 80 mg). Patients in the magnesium sulfate group received a 6-g bolus followed by 2 to 4 g/h to provide uterine quiescence. Patients could be switched to another tocolytic regimen if they continued to have contractions after 6 hours of therapy. The main outcome variables examined were time to uterine quiescence, time gained in utero, recurrence of preterm labor, failure of tocolysis, and pertinent maternal and neonatal outcomes. RESULTS: There were no significant differences in maternal demographic characteristics between the groups. Among patients who responded with uterine quiescence within 6 hours, there was a significant decrease in the time to uterine quiescence in the nicardipine group (P <.01). Patients in the magnesium sulfate group were more likely to have recurrence of preterm labor necessitating further tocolytic attempts (P =.048). The patients in the magnesium sulfate group had more adverse side effects, mainly nausea and vomiting (P =.004). There were no differences in birth weight, estimated gestational age at delivery, or neonatal complications between the 2 groups. CONCLUSIONS: Oral nicardipine is an effective, safe, and well-tolerated tocolytic agent. In this prospective clinical trial patients randomly assigned to receive oral nicardipine had arrest of preterm labor more rapidly than did those randomly assigned to receive parenteral magnesium sulfate. Patients who received magnesium sulfate were more likely to have adverse medication effects and recurrent preterm labor.     

Qualitative human chorionicgonadotropin testing of cervicovaginal washings for the detection of preterm premature rupture of membranes

OBJECTIVE: This study was performed to determine whether a qualitative human chorionicgonadotropin (hCG) test using cervicovaginal washings obtained from pregnant women is a useful predictor of recent preterm premature rupture of the membranes (PPROM). STUDY DESIGN: A prospective observational analysis of qualitative hCG testing on cervicovaginal washings in patients with either known PPROM or with intact membranes was performed. Patients with singleton gestations between 24 and 34 completed weeks were included. PPROM patients had documented confirmatory tests, including visualized pooling of amniotic fluid in the vaginal vault that was nitrazine-positive and demonstrated ferning. Those with vaginal bleeding or an anomalous fetus were excluded. Before collection, all patients were screened for bacterial vaginosis and trichomoniasis. Washings were then collected from the posterior vaginal fornix with the use of a 5-mL sterile saline irrigation and aspiration technique. Samples were then agitated manually and applied to the Quickvue Onestep qualitative pregnancy test (Quidell, San Diego, Calif) with a threshold of 25 mIU/mL. Data were analyzed with the t test, chi 2, and Fischer exact tests. Sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values were calculated. When applicable, all 2-tailed P <.05 were considered significant. RESULTS: Fifty-two patients were enrolled in the study with 24 in the PPROM group and 28 in the control group. The 2 groups were similar with respect to demographic characteristics and wet preparation results. The mean gestation age was 31.4 +/- 2.4 (X +/- SD) and 30.8 +/- 2.7 weeks in the PPROM and control groups, respectively. The hCG test was positive in 19 (79%) of the PPROM patients and in 1 (3.6%) of the controls (sensitivity 79%, specificity 96%, PPV 95%, NPV 84%). CONCLUSION: Qualitative hCG testing of cervicovaginal washings appears to be an useful predictor of PPROM.     

Duration of antibiotic therapy after preterm premature rupture of fetal membranes

OBJECTIVE: This study was undertaken to compare the efficacy of 3 days versus 7 days of ampicillin in prolonging gestation for at least 7 days in women with preterm premature rupture of membranes (PPROM). STUDY DESIGN: We performed a randomized clinical trial comparing 3 days of ampicillin with 7 days ampicillin in patients with PPROM. Our primary outcome was the prolongation of pregnancy for at least 7 days. Secondary outcomes included rates of chorioamnionitis, postpartum endometritis, and neonatal morbidity and mortality. RESULTS: Forty-eight patients were randomly selected. There was no statistically significant difference in the ability to achieve a 7-day latency (relative risk 0.83, 95% CI 0.51-1.38). In addition, there was no statistically significant difference in the rates of chorioamnionitis, endometritis, and our composite neonatal morbidity. CONCLUSION: In patients with PPROM, length of antibiotic therapy does not change the rate of a 7-day latency or affect the rate of chorioamnionitis, postpartum endometritis, or neonatal morbidity.     

The timing of elective delivery in preterm premature rupture of the membranes: a survey of members of the Society of Maternal-Fetal Medicine

OBJECTIVE: We sought to assess the gestational age at which elective delivery is considered in an otherwise uncomplicated patient with preterm premature rupture of the membranes (PROM) by members of the Society of Maternal Fetal-Medicine (SMFM). STUDY DESIGN: A 3-page survey was mailed to members of the SMFM for this observational study. Information solicited included demographic data and practice patterns for the timing of delivery in patients with preterm PROM. RESULTS: Seven hundred seventeen questionnaires (40%) were completed. The majority (81%) did not believe there is a consensus regarding the gestational age for elective delivery in patients with preterm PROM. With confirmed fetal lung maturity, the greatest number of respondents selected 32 and 34 weeks as the earliest gestational age for elective delivery. In the absence of fetal pulmonary maturity testing, the majority of respondents chose 34 weeks. CONCLUSION: Most SMFM respondents electively deliver uncomplicated patients with preterm PROM by 34 weeks' gestation.     

Transcervical intrapartum amnioinfusion for preterm premature rupture of the membranes

OBJECTIVES: To investigate the effect of transcervical amnioinfusion on the management of labour and neonatal outcomes in preterm premature rupture of the membranes. STUDY DESIGN: This clinical trial included 86 patients with premature rupture of the membranes between weeks 27 and 35 of gestation. Patients were randomly assigned to receive amnioinfusion via a two-way catheter or to the control group. Clinical management was otherwise the same in both groups. RESULTS: Amnioinfusion decreased the frequency of variable decelerations in fetal heart rate (27.9% versus 53.5%, p<0.05) and the rate of obstetric interventions motivated by nonreassuring fetal status (13.6% versus 52.4%, p<0.05). At delivery, pH values were significantly higher in the treatment group than in the conventionally managed control group (median 7.29 versus 7.27). CONCLUSIONS: Intrapartum transcervical amnioinfusion for preterm premature rupture of the membranes reduced the number of interventions needed because of nonreassuring fetal status, and improved neonatal gasometric values without increasing maternal or fetal morbidity.     

Difficulties in establishing routine amniocentesis for preterm labor evaluation

After a recent practice change implementing amniocentesis into the evaluation of preterm labor (PTL) or preterm premature rupture of membranes (PPROM), actual performance of the procedure was tracked. Fifty-nine patients were admitted with these diagnoses. Twenty-three patients (39%) were offered amniocentesis and 36 patients (61%) were not offered amniocentesis as part of the clinical protocol. Seven (30%) patients of those offered an amniocentesis underwent the procedure. The predominant reasons for not performing an amniocentesis were patient refusal and provider discomfort. In conclusion, implementation of amniocentesis to evaluate for subclinical infection/inflammation in the setting of PTL or PPROM proved difficult, as only 7 of 59 (11.9%) patients admitted with these diagnoses actually received an amniocentesis.