Metformin Plus Insulin for Preexisting Diabetes or Gestational Diabetes in Early Pregnancy: The MOMPOD Randomized Clinical Trial

Importance

Insulin is recommended for pregnant persons with preexisting type 2 diabetes or diabetes diagnosed early in pregnancy. The addition of metformin to insulin may improve neonatal outcomes.

Objective

To estimate the effect of metformin added to insulin for preexisting type 2 or diabetes diagnosed early in pregnancy on a composite adverse neonatal outcome.

Design, Setting, and Participants

This randomized clinical trial in 17 US centers enrolled pregnant adults aged 18 to 45 years with preexisting type 2 diabetes or diabetes diagnosed prior to 23 weeks' gestation between April 2019 and November 2021. Each participant was treated with insulin and was assigned to add either metformin or placebo. Follow-up was completed in May 2022.

Intervention

Metformin 1000 mg or placebo orally twice per day from enrollment (11 weeks -<23 weeks) through delivery.

Main Outcome and Measures

The primary outcome was a composite of neonatal complications including perinatal death, preterm birth, large or small for gestational age, and hyperbilirubinemia requiring phototherapy. Prespecified secondary outcomes included maternal hypoglycemia and neonatal fat mass at birth, and prespecified subgroup analyses by maternal body mass index less than 30 vs 30 or greater and those with preexisting vs diabetes early in pregnancy.

Results

Of the 831 participants randomized, 794 took at least 1 dose of the study agent and were included in the primary analysis (397 in the placebo group and 397 in the metformin group). Participants' mean (SD) age was 32.9 (5.6) years; 234 (29%) were Black, and 412 (52%) were Hispanic. The composite adverse neonatal outcome occurred in 280 (71%) of the metformin group and in 292 (74%) of the placebo group (adjusted odds ratio, 0.86 [95% CI 0.63-1.19]). The most commonly occurring events in the primary outcome in both groups were preterm birth, neonatal hypoglycemia, and delivery of a large-for-gestational-age infant. The study was halted at 75% accrual for futility in detecting a significant difference in the primary outcome. Prespecified secondary outcomes and subgroup analyses were similar between groups. Of individual components of the composite adverse neonatal outcome, metformin-exposed neonates had lower odds to be large for gestational age (adjusted odds ratio, 0.63 [95% CI, 0.46-0.86]) when compared with the placebo group.

Conclusions and Relevance

Using metformin plus insulin to treat preexisting type 2 or gestational diabetes diagnosed early in pregnancy did not reduce a composite neonatal adverse outcome. The effect of reduction in odds of a large-for-gestational-age infant observed after adding metformin to insulin warrants further investigation.

Trial Registration

ClinicalTrials.gov Identifier: NCT02932475.

Lactation Leads to Modifications in Maternal Renin-Angiotensin System in Later Life

The objective of this study was to evaluate whether the renin-angiotensin system (RAS) is associated with maternal cardioprotective phenotype observed in post-lactated mice later in life. Following the delivery, CD-1 female mice were randomized to one of the following groups: lactated (nursed pups for 3 weeks, n = 10) or non-lactated (pups were removed after birth, n = 10). The mice were sacrificed 6 months after the delivery, and tissues were collected. Protein levels of angiotensinogen, angiotensin type 1 and 2 receptors (AT1R, AT2R), angiotensin converting enzymes (ACE, ACE2), and MAS receptor were determined using Western blot. Results were analyzed using Student's t-test and Mann-Whitney test as appropriate (significance: P < 0.05). Angiotensinogen levels were significantly lower in the liver (P = 0.0002), and ACE was significantly decreased in the lungs (P = 0.04) and kidney (P = 0.001) from lactated mice as compared to non-lactated. The levels of AT2R in the kidney (P = 0.02) and visceral adipose tissue (VAT, P = 0.04), the ACE 2 in the VAT (P = 0.03) and heart (P = 0.04), and MAS receptor in VAT (P = 0.02) were significantly elevated in tissues from lactated mice. No other differences were found. Lactation led to the upregulation and downregulation of selected RAS components in lactated mice as compared to non-lactated group and may be a contributing factor to maternal cardioprotective phenotype later in life. Further studies are needed to dissect the mechanisms between lactation and the long-term maternal cardiometabolic benefits, which could lead to the therapies to prevent cardiovascular disease in women.

The Effect of Distraction during Labor Induction on Timing of Analgesia Request: A Randomized Clinical Trial

OBJECTIVE

To assess whether distraction using music and/or video games influences timing of analgesia request and improves pain outcomes in women undergoing labor induction.

STUDY DESIGN

A total of 219 pregnant women with singleton gestation undergoing labor induction with a Foley bulb (FB) at term were randomized to distraction with music and video games via iPod (n = 109) or no iPod (n = 110). The primary outcome was the time from FB placement to request for pain medication. Secondary outcomes included number of patients requesting pain medication within 6 and 12 hours, type of pain medication received, pain visual analog scale scores, and patient satisfaction. Mann-Whitney's, chi-square, Kaplan-Meier's curves, and Pearson's product moment correlation were used for statistical analysis (significance: p < 0.05).

RESULTS

Baseline characteristics were similar between the two groups. There was no difference in the time from FB placement until pain medication request between the groups. There were no significant differences in secondary outcomes. Increased per cent time of iPod use correlated with a longer time until pain medication request (R ² = 0.22, p = 0.03).

CONCLUSION

We were not able to show that distraction using music and video games delays timing of analgesia request or improve pain outcomes in pregnant women undergoing mechanical labor induction at term.

Long-Term Effect of Lactation on Maternal Cardiovascular Function and Adiposity in a Murine Model

OBJECTIVE

Epidemiological studies suggest that lactation is associated with long-term maternal health benefits. To avoid confounders in human studies, we used a previously characterized murine model to investigate the long-term effect of lactation on both cardiovascular function and adiposity.

STUDY DESIGN

After the delivery of the pups, CD-1 female mice were randomly divided into two groups: lactated and nonlactated (NL). Before pregnancy and at 9 months postdelivery, blood pressure was measured using a tail cuff, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were assessed by computed tomography (CT), echocardiography was performed using microultrasound, and cholesterol panels and fasting blood glucose were measured. The data were analyzed using Student's t-test (significance at p < 0.05).

RESULTS

There were no differences in baseline parameters between the two groups. At 9 months postdelivery, the NL group weighed significantly more (p = 0.03) and demonstrated a significantly lower cardiac output (p = 0.05) and ejection fraction (p = 0.03). The mice in the NL group also had higher VAT (p < 0.01) and SAT percentiles (p = 0.03). Fasting glucose (p = 0.01) and low-density lipoprotein (p = 0.01) were significantly higher in the NL group at 9 months.

CONCLUSION

Our results show the benefit of lactation is not just limited to the immediate postpartum period but it also extends into midlife in a murine model.

The Effect of Wearing White Coats on Patients' Appreciation of Physician Communication during Postpartum Rounds: A Randomized Controlled Trial

OBJECTIVE

Wearing a white coat (WC) has been associated with risk of colonization and transmission of resistant pathogens. Also, studies have shown that physicians' attire in general affects patients' confidence in their physician and the patient-physician relationship. Our objective is to evaluate the hypothesis that not wearing a WC during physician postpartum rounds does not affect patient-physician communication scores.

MATERIALS AND METHODS

This is an unblinded, randomized, parallel arms, controlled trial of postpartum women at a single university hospital. Women were randomly assigned to having their postpartum physicians' team wear a WC or not (no-WC) during rounds. Our primary outcome was "patient-physician communication" score. Univariable and multivariable analysis were used where appropriate.

RESULTS

One hundred and seventy-eight patients were enrolled (87 in WC and 91 in no-WC groups). Note that 40.4% of patients did not remember whether the physicians wore a WC or not. There was no difference in the primary outcome (p = 0.64) even after adjusting for possible confounders.

CONCLUSION

Not wearing a WC during postpartum rounds did not affect the patient-physician communication or patient satisfaction scores. In the setting of prior reports showing a risk of WC pathogen transmission between patients, our findings cannot support the routine wearing of WCs during postpartum rounds.

Pfannenstiel versus Vertical Skin Incision for Cesarean Delivery in Women with Class III Obesity: A Randomized Trial

OBJECTIVE

To compare Pfannenstiel versus vertical skin incision for the prevention of cesarean wound complications in morbidly obese women.

STUDY DESIGN

Women with body mass index ≥ 40 kg/m² undergoing cesarean delivery (CD) were randomly allocated to Pfannenstiel or vertical skin incision. The primary outcome was a wound complication within 6 weeks. Due to a low consent rate, we limited enrollment to a defined time period for feasibility. We conducted a traditional frequentist analysis with log-binomial regression to obtain relative risks (RRs), and a Bayesian analysis to estimate the probability of treatment benefit. A priori, we decided that a ≥60% probability of treatment benefit for either incision type would be convincing evidence to pursue a larger trial.

RESULTS

A total of 648 women were approached, 228 were consented, and 91 were randomized. The primary outcome rate was 19% in the Pfannenstiel group and 21% in the vertical group (RR: 1.18; 95% confidence interval: 0.49-2.85). Bayesian analysis revealed a 59% probability that Pfannenstiel had a lower primary outcome rate.

CONCLUSION

In the first published randomized trial to compare skin incision types for obese women undergoing CD, we were unable to demonstrate differences in clinical outcomes. Our trial suggests that a larger study would have a low probability for different findings.

TRIAL REGISTRATION

NCT 01897376 (www.clinicaltrials.gov).

The association of hyperuricemia and immediate postpartum hypertension in women without a diagnosis of chronic hypertension

Our objective was to determine if elevated uric acid (UA) is associated with postpartum hypertension (PP HTN) in women without chronic hypertension. This is a secondary analysis of a randomized trial. We compared those with elevated UA to those with normal UA. Logistic regression was conducted to determine the association of elevated UA with PP HTN. Five hundred and fifty-six women met criteria. An UA level ≥ 5.2 mg/dL was associated with immediate PP HTN (adjusted odds ratio 2.44, 95% CI 1.63-3.64). The association was stronger among overweight and obese women. We conclude that hyperuricemia is associated with PP HTN, especially among obese women.

Neurocysticercosis in Pregnancy

The normal physiologic changes during pregnancy contribute to nutritional, metabolic, and immunologic adjustments, which can have an impact on the presentation of several diseases. New onset seizures during pregnancy and the postpartum can be attributed to several etiologies. Patient demographic data as well as personal and social histories are key in determining the etiology of new onset seizures. Neurocysticercosis (NCC), a commonly overlooked etiology, must be included in the differential diagnosis of patients with new onset seizures coming from NCC endemic areas. The diagnosis is based on a combination of clinical findings, exposure history, imaging, and serology. We present two cases of patients with NCC that became symptomatic during pregnancy or postpartum period. We will review the epidemiology, clinical manifestations, and management of NCC in pregnancy.

Adipose Tissue Insulin Resistance in Gestational Diabetes

BACKGROUND

Gestational diabetes mellitus (GDM) is a metabolic disorder characterized by insulin resistance (IR) and altered glucose-lipid metabolism. We propose that ectonucleotide pyrophosphate phosphodiesterase-1 (ENPP1), a protein known to induce adipocyte IR, is a determinant of GDM. Our objective was to study ENPP1 expression in adipose tissue (AT) of obese pregnant women with or without GDM, as well as glucose tolerance in pregnant transgenic (Tg) mice with AT-specific overexpression of human ENPP1.

METHODS

AT biopsies and blood were collected from body mass index-matched obese pregnant women non-GDM (n = 6), GDM (n = 7), and nonpregnant controls (n = 6) undergoing cesarian section or elective surgeries, respectively. We measured the following: (1) Expression of key molecules involved in insulin signaling and glucose-lipid metabolism in AT; (2) Plasma glucose and insulin levels and calculation of homeostasis model assessment of IR (HOMA-IR); (3) Intraperitoneal glucose tolerance test in AtENPP1 Tg pregnant mice.

RESULTS

We found that: (1) Obese GDM patients have higher AT ENPP1 expression than obese non-GDM patients, or controls (P = 0.01-ANOVA). (2) ENPP1 expression level correlated negatively with glucose transporter 4 (GLUT4) and positively with insulin receptor substrate-1 (IRS-1) serine phosphorylation, and to other adipocyte functional proteins involved in glucose and lipid metabolism (P < 0.05 each), (3) AT ENPP1 expression levels were positively correlated with HOMA-IR (P = 0.01-ANOVA). (4) Pregnant AT ENPP1 Tg mice showed higher plasma glucose than wild type animals (P = 0.046-t test on area under curve [AUC]_glucose).

CONCLUSIONS

Our results provide evidence of a causative link between ENPP1 and alterations in insulin signaling, glucose uptake, and lipid metabolism in subcutaneous abdominal AT of GDM, which may mediate IR and hyperglycemia in GDM.

Zika Virus and Pregnancy: A Review of the Literature and Clinical Considerations

The latest Zika virus (ZIKV) outbreak has reached epidemic proportions as it spreads throughout South and Central America. In November 2015, the Brazilian Ministry of Health reported a 20-fold increase in the number of cases of neonatal microcephaly, which corresponds geographically and temporally to the ZIKV outbreak. Case reports have provided some evidence of a causal link between maternal ZIKV infection, fetal microcephaly, and intracranial calcifications. The sparse data regarding ZIKV in pregnancy come solely from case reports and personal communications, and recommendations for management of ZIKV exposure during pregnancy are rapidly evolving. Our objective is to review and synthesize the current literature regarding ZIKV as it pertains to pregnancy and provide some assistance to clinicians who may have to manage a pregnant patient with potential exposure to ZIKV. We will also explore certain aspects of related viruses in pregnancy in hopes to shed light on this little-known topic.

Extending the scope of pooled analyses of individual patient biomarker data from heterogeneous laboratory platforms and cohorts using merging algorithms

BACKGROUND

A common challenge in medicine, exemplified in the analysis of biomarker data, is that large studies are needed for sufficient statistical power. Often, this may only be achievable by aggregating multiple cohorts. However, different studies may use disparate platforms for laboratory analysis, which can hinder merging.

METHODS

Using circulating placental growth factor (PlGF), a potential biomarker for hypertensive disorders of pregnancy (HDP) such as preeclampsia, as an example, we investigated how such issues can be overcome by inter-platform standardization and merging algorithms. We studied 16,462 pregnancies from 22 study cohorts. PlGF measurements (gestational age ⩾20 weeks) analyzed on one of four platforms: R&D Systems, AlereTriage, RocheElecsys or AbbottArchitect, were available for 13,429 women. Two merging algorithms, using Z-Score and Multiple of Median transformations, were applied.

RESULTS

Best reference curves (BRC), based on merged, transformed PlGF measurements in uncomplicated pregnancy across six gestational age groups, were estimated. Identification of HDP by these PlGF-BRCs was compared to that of platform-specific curves.

CONCLUSIONS

We demonstrate the feasibility of merging PlGF concentrations from different analytical platforms. Overall BRC identification of HDP performed at least as well as platform-specific curves. Our method can be extended to any set of biomarkers obtained from different laboratory platforms in any field. Merged biomarker data from multiple studies will improve statistical power and enlarge our understanding of the pathophysiology and management of medical syndromes.

Relation between birth weight and weight and height at the age of 2 in children born preterm

OBJECTIVE

The aim of the study was to evaluate associations between fetal growth and weight at 2 years in infants born preterm using a customized approach for birth weight.

STUDY DESIGN

This is a secondary analysis of a multicenter trial that included a 2-year follow-up of children born prematurely. Customized birth weight percentiles were calculated using the Gardosi model for a U.S. population, and the relation between customized percentile and weight and height at 2 years (adjusted for gender using z-score) was determined using regression analysis and by comparing z-scores for children with birth weight <10th versus ≥10th percentile.

RESULTS

Weight z-score at 2 years was significantly lower in the <10th than in the ≥10th percentile group (median [interquartile range, IQR]: -0.66 [-1.58, -0.01] vs. -0.23 [-1.05, 0.55]; p < 0.001), and remained after adjusting for maternal education (p < 0.001). A similar relationship was noted for height z-score between groups (median [IQR]: -0.56 [-1.29, 0.19] vs. -0.24 [-0.99, 0.37]; p < 0.001). Positive relationships between customized birth weight percentile and weight and height at 2 years were noted (p < 0.001 for both), but were not strong (R (2) = 0.04 and 0.02, respectively).

CONCLUSION

Customized birth weight percentile is a minor determinant of weight at 2 years among children born preterm.

Optimization of gestational weight gain in the obese gravida: a review

Because of the consistent association between gestational weight gain and birth weight (along with other maternal and child outcomes such as postpartum weight retention and child obesity), helping women avoid excessive weight gain during pregnancy should be an important objective of prenatal and preconceptional care. This article focuses on the updated Institute of Medicine gestational weight gain recommendations and measures directed at maintaining those guidelines and improving pregnancy outcome.

Disseminated Intravascular Coagulation, Hemoperitoneum, and Reversible Ischemic Neurological Deficit Complicating Anaphylaxis to Prophylactic Antibiotics during Cesarean Delivery: A Case Report and Review of Literature

Routine use of prophylactic antibiotics reduces the risk of postcesarean fever and infections by over 50% in both nonelective and elective (scheduled) procedures. Although anaphylaxis to prophylactic antibiotics is rare, potentially fatal complications might occur. Herein, we present a case where disseminated intravascular coagulation and reversible ischemic neurological deficit complicated anaphylactic reactions to prophylactic antibiotics administered during cesarean delivery. A 27-year-old gravida 9, para 7 at 39(2)/7 weeks underwent elective repeat cesarean delivery and bilateral tubal ligation. Her surgery was complicated by intraoperative hypotension, generalized itching, and urticarial skin rash consistent with anaphylactic reaction upon administering prophylactic cefazolin. In the recovery room, she continued to be hemodynamically unstable despite energetic resuscitation. Hemoperitoneum was suspected, and laboratory evaluation indicated disseminated intravascular coagulation. Abdominal exploration revealed massive hemoperitoneum, but there was no source of active bleeding noted. The postoperative course was complicated by reversible ischemic neurological deficit, which resolved on expectant management. Disseminated intravascular coagulation and reversible ischemic neurological deficit may complicate anaphylactic reaction to prophylactic antibiotics administered during cesarean delivery. Immediate recognition and intervention is crucial for a successful outcome.

Non-invasive transabdominal uterine electromyography correlates with the strength of intrauterine pressure and is predictive of labor and delivery

OBJECTIVE

The study was conducted to investigate whether the strength of uterine contractions monitored invasively by intrauterine pressure catheter could be determined from transabdominal electromyography (EMG) and to estimate whether EMG is a better predictor of true labor compared to tocodynamometry (TOCO).

STUDY DESIGN

Uterine EMG was recorded from the abdominal surface in laboring patients simultaneously monitored with an intrauterine pressure catheter (n = 13) or TOCO (n = 24). Three to five contractions per patient and corresponding electrical bursts were randomly selected and analyzed (integral of intrauterine pressure; integral, frequency, amplitude of contraction curve on TOCO; burst energy for EMG). The Mann-Whitney test, Spearman correlation and receiver operator characteristics (ROC) analysis were used as appropriate (significance was assumed at a value of p < 0.05).

RESULTS

EMG correlated strongly with intrauterine pressure (r = 0.764; p = 0.002). EMG burst energy levels were significantly higher in patients who delivered within 48 h compared to those who delivered later (median [25%/75%]: 96,640 [26,520-322,240] vs. 2960 [1560-10,240]; p < 0.001), whereas none of the TOCO parameters were different. In addition, burst energy levels were highly predictive of delivery within 48 h (AUC = 0.9531; p < 0.0001).

CONCLUSION

EMG measurements correlated strongly with the strength of contractions and therefore may be a valuable alternative to invasive measurement of intrauterine pressure. Unlike TOCO, transabdominal uterine EMG can be used reliably to predict labor and delivery.

Preterm labor: CD55 in maternal blood leukocytes

PROBLEM

Intrauterine inflammation is a frequent and significant factor associated with the pathogenesis of preterm labor/birth (PTL/PTB). However, it remains unclear whether the intrauterine inflammatory responses activate the maternal peripheral circulation. We explored the association between PTL/PTB and the 'activation' of the peripheral circulatory system by determining whether CD55 mRNA expression within peripheral WBCs differed between PTL and control patients not in labor.

METHOD OF STUDY

RNA was purified from white blood cells collected from pregnant women with preterm labor (n = 45), and from pregnant (n = 30) control women. CD55 gene expression was evaluated by quantitative PCR.

RESULTS

The mean CD55 mRNA level within the PTL group (0.77 +/- 0.03) was 1.48-fold higher than that observed (0.52 +/- 0.02) within the control group (P < 0.0001); 71% of PTL patients and only 6.7% of control subjects expressed elevated CD55 mRNA. The receiver operating characteristics (with 95% CI) of CD55 as a marker for PTL were as follows: Sensitivity, 69% (53-82%); Specificity, 93% (78-99%); Positive Predictive Value, 94% (80-99%); and Negative Predictive Value, 67% (51-80%). In the patient population that delivered prematurely (before 37 weeks), 81% expressed elevated CD55 mRNA levels with a mean of 0.78 +/- 0.03 and 95% CI of 0.71-0.84. The receiver operating characteristics were as follows: Sensitivity, 73% (54-88%); Specificity, 86% (71-95%); Positive Predictive Value, 81.5% (62-94%); and Negative Predictive Value, 80% (64-91%).

CONCLUSION

Here we report for the first time that CD55 mRNA expression was elevated in the peripheral WBCs of subjects with preterm labor compared with control gestationally-matched pregnant woman and that elevated leukocyte CD55 may be a useful predictor of subsequent PTB.

A multi-institutional effort for temporary training of residents displaced by disaster: lessons from Katrina

OBJECTIVE

This study was undertaken to describe a comprehensive, collaborative temporary residency training curriculum after disaster.

STUDY DESIGN

The Texas Southeast Alliance was created in response to the Katrina Disaster by regional obstetric/gynecology programs. Principles were devised to guide development of a temporary training curriculum. Learning opportunities were identified and pooled. Affected program directors were contacted who expressed interest in the curriculum which had been approved by institutional officials and appropriate regulatory bodies.

RESULTS

In total, 41 different training opportunities were made available to the Tulane residents. Twenty-four residents completed 92 rotations in total. Residents met weekly with their program director. Free psychiatric consultative services were provided through resident counseling services. Housing was facilitated wherever possible.

CONCLUSION

Consolidation of resources by the Texas Southeast Alliance provided temporary training experiences for Tulane obstetric and gynecology residents displaced by Hurricane Katrina. Effective training can be maintained after disaster by coordinating institutional efforts and establishing governing principles.

Light-induced fluorescence of the human cervix decreases after prostaglandin application for induction of labor at term

OBJECTIVE

To define the changes in cervical light-induced fluorescence (LIF), an index of cross-linked collagen, after the use of locally applied prostaglandin preparations for labor induction at term and the correlation between LIF and Bishop-Score.

STUDY DESIGN

The characteristic LIF of cervical collagen was measured from the surface of the cervix using a specially designed instrument (collascope) in 41 gravidas undergoing labor induction at term by prostaglandins. LIF and Bishop-Score were obtained directly before and 4h after the administration of prostaglandin. Paired Student's t-test, Wilcoxon Signed Rank test, Linear Regression, Spearman correlation and Fisher Exact test were used as appropriate.

RESULTS

Cervical LIF decreased significantly after prostaglandin application (0.982+/-0.04 [before] to 0.885+/-0.037 [after], p=0.025). The decrease in LIF correlated with the initial LIF before PG-application (r=0.61). The Bishop-Score increased in all 41 patients. No correlation was found between LIF versus Bishop-Score.

CONCLUSIONS

Cervical application of prostaglandins decreases the amount of cross-linked collagen as measured by LIF. This effect was observed only in patients with a prior high cross-linked collagen.

Predicting term and preterm delivery with transabdominal uterine electromyography

OBJECTIVE

To determine whether delivery can be predicted using transabdominal uterine electromyography.

METHODS

A total of 99 patients were grouped as either term (37 weeks or more) or preterm (less than 37 weeks). Uterine electrical activity was recorded for 30 minutes in clinic. Electromyographic "bursts" were evaluated to determine the power density spectrum. Measurement-to-delivery time was compared with the average power density spectrum's peak frequency. Receiver operating characteristic curve analysis was performed for 48, 24, 12, and 8 hours from term delivery, and 6, 4, 2, and 1 day(s) from preterm delivery.

RESULTS

The power density spectrum peak frequency increased as the measurement-to-delivery interval decreased. Receiver operating characteristic curve analysis gave high positive and negative predictive values for both term and preterm delivery. At term, the average power density spectrum peak frequency was significantly higher for the 24-or-fewer-hours-to-delivery group than for the more-than-24-hours-to-delivery group, whereas at preterm, the average power density spectrum peak frequency was significantly higher in the 4-or-fewer-days-to-delivery group than in the more-than-4-days-to-delivery group (P <.05).

CONCLUSION

Transabdominal uterine electromyography predicts delivery within 24 hours at term and within 4 days preterm. This methodology offers many advantages and benefits that are not available with present uterine monitoring systems.

Amniotic fluid index measured with the aid of color flow Doppler

OBJECTIVE

To determine whether using color flow Doppler to identify the umbilical cord affects amniotic fluid index (AFI) measurements.

METHODS

A total of 2236 AFI measurements between 24 and 42 weeks in singleton gestations with no known or suspected fetal anomalies and < 14 days' discrepancy between menstrual and ultrasonographic dating were included. Color flow Doppler was used to identify loops of umbilical cord; these were excluded from the measurement. Polynomial regression was used to generate means and centiles. Data were grouped according to completed weeks of gestation and descriptive statistics were calculated. At each week of gestation, the number and percentage of pregnancies diagnosed as < or = 2.5th, < or = 5th, > or = 95th, and > or = 97.5th centile according to a 'standard' nomogram derived without using color flow Doppler were calculated.

RESULTS

The AFI decreased significantly over gestational age, starting at 31 weeks (p < 0.05 by ANOVA). The relationship between AFI and gestational age was best modeled by a second-degree polynomial (p < 0.001). The median and range of the proportion of AFIs that fell outside the ranges of the standard nomogram at each completed gestational age was: 6.0 (2.3-35.4)% for the < or = 2.5th centile, 9.9 (3.1-37.5)% for the < or = 5th centile, 3.8 (0-30)% for the > or = 95th centile, and 1.8 (0-20)% for the > or = 97.5th centile. The 2.5th and 5th centiles using the current data were lower than those of the 'standard', and the difference increased with advancing gestation. Upper centiles were also different.

CONCLUSION

The AFI measured using color flow Doppler overestimates oligohydramnios and may underestimate polyhydramnios when a standard AFI table obtained without color flow Doppler is used. Normal values specific for measurement method should be used for reference.

Cervical light-induced fluorescence in humans decreases throughout gestation and before delivery: Preliminary observations

OBJECTIVE

The purpose of this study was to investigate gestational changes of cervical light-induced fluorescence, an index of cross-linked collagen, and the relationship between light-induced fluorescence and the time-to-delivery interval.

STUDY DESIGN

Fifty patients were included in one of two groups. (1) Twenty-one healthy pregnant women without signs of labor underwent repeated cervical light-induced fluorescence measurement during the last trimester. (2) Light-induced fluorescence was measured in 29 patients with signs of labor, and the time from measurement to delivery was noted. Cervical light-induced fluorescence was obtained noninvasively with a prototype instrument that was designed specifically for this purpose. Spearman correlation and the Student t test and receiver-operator characteristics analysis were performed (P <.05).

RESULTS

Light-induced fluorescence correlated negatively with gestational age and positively with time-to-delivery interval, was significantly lower in patients who were delivered <24 hours compared with those patients who were delivered >24 hours later, and was predictive of delivery within 24 hours.

CONCLUSION

Cervical light-induced fluorescence decreases significantly as gestational age increases. Light-induced fluorescence may be a useful tool to identify patients in whom delivery is imminent.

Uterine electromyography and light-induced fluorescence in the management of term and preterm labor

OBJECTIVE

Understanding the physiology of the uterus and cervix during term and preterm parturition is crucial for developing methods to control their function and is essential to solving clinical problems related to labor. To date, only crude, inaccurate, and subjective methods are used to assess changes in uterine and cervical function in pregnancy.

METHODS

In the past several years, we have developed noninvasive methods to quantitatively evaluate the uterus and cervix based on recording of uterine electrical signals from the abdominal surface (uterine electromyography) and measurement of light-induced fluorescence (LIF) of cervical collagen (Collascope), respectively. Both methods are rapid and allow immediate assessment of uterine contractility and cervical ripening.

RESULTS

Studies in animals and humans indicated that uterine and cervical performance can be monitored successfully during pregnancy using those approaches and that these techniques can be used during labor to better define management in a variety of conditions associated with labor.

CONCLUSION

The potential benefits of the proposed instrumentation and methods include reducing the rate of preterm delivery, improving maternal and perinatal outcome, monitoring treatment, decreasing cesarean rate and providing research methods to understand uterine and cervical function.

Changes in light-induced fluorescence of cervical collagen in guinea pigs during gestation and after sodium nitroprusside treatment

Light-induced fluorescence (LIF) of collagen was used to investigate in vivo changes in cervical collagen in guinea pigs during gestation and following sodium nitroprusside treatment. Natural fluorescence of collagen is due to collagen cross-linking molecules that connect single collagen fibers and therefore provide rigidity of the cervical stroma. LIF of cervical collagen was measured from the surface of the exocervix in anesthetized nonpregnant and timed pregnant guinea pigs at different times of gestation with an instrument designed in our lab (Collascope). Measurements were also performed in guinea pigs at midgestation before and 8 hours after intracervical treatment with sodium nitroprusside. Collagen fluorescence decreased significantly as pregnancy progressed, reached lowest values at delivery, and increased gradually postpartum. Treatment with sodium nitroprusside, but not with the vehicle, caused a significant decrease in LIF (p = 0.007). We conclude, that LIF changes in the cervix reflect the gradual cervical softening (ripening) during pregnancy and the return to the rigid state of the cervix postpartum. Cervical softening during pregnancy, and after sodium nitroprusside treatment, is associated with a decrease in collagen cross-links. Measurements of LIF can be used to investigate cervical softening in vivo.