Optical properties of human amniotic fluid: implications for videofetoscopic surgery.

OBJECTIVE: Videofetoscopy typically demands the substitution of oft-turbid amniotic fluid with clear crystalloid. This maneuver can be cumbersome and may lead to complications. We sought to determine the optical properties of the amniotic fluid, as a pre-requisite for optimizing video image processing during videofetoscopy and eventually avoid amniotic fluid replacement. METHODS: Human amniotic fluid samples (n = 21) were procured at 19-36 weeks of gestation. Optical refraction and reflection indices were recorded as percentages of light transmission through the fluid using an integrated spectrometer covering wavelengths of 400-950 nm, with 1.0 nm resolution. Statistical analysis was by one-way ANOVA (p < 0.05). RESULTS: Peak optical refraction fell within a relatively limited window of the near-infrared spectrum, at 848.1 +/- 52.3 nm, regardless of gestational age or overall light absorbance. Within the visible spectrum, transmission was highest at the highest wavelengths. A statistically significant inverse relationship existed between gestational age and overall light transmission. Light reflection was negligible in all samples. CONCLUSIONS: Light transmission through amniotic fluid is optimal in the near-infrared spectrum and at the highest visible wavelengths, regardless of gestational age. Overall light transmission through amniotic fluid decreases throughout gestation. The light source and camera of videofetoscopy systems should be designed accordingly, possibly obviating the need for routine intraoperative amniotic fluid exchange.

Spinal cord stimulation and the pregnant patient-specific considerations for management: A case series and review of the literature.

OBJECTIVES: The use of spinal cord stimulation (SCS) is a form of neuromodulation used to treat chronic pain in those patients who are refractory to conventional medical management. Not uncommonly, SCS can dramatically improve a patient's quality of life, and those who are in the childbearing years may go on to become pregnant. The purpose of this case series is to describe: 1) implantation considerations in women of childbearing age; 2) use of rechargeable systems; 3) the obstetric and anesthetic concerns in patients with spinal cord stimulators; 4) risks of using SCS in the peripartum period. MATERIALS AND METHODS: Two female patients with complex regional pain syndrome I (CRPS I) who were well managed with SCS became pregnant. In both patients, the leads were placed through the T12/L1 interspace and the generator was placed in the buttock region. In the first patient, the device was deactivated prior to conception and maintained off for the duration of the pregnancy. The second patient became pregnant on two separate occasions, with active SCS for a portion of the first trimester. During her second pregnancy, the patient elected to use of SCS at 30 weeks' gestation. RESULTS: The developing fetuses with intrauterine exposure to SCS were followed out for a minimum of two years and are developmentally normal. The physical presence of the device did not complicate obstetric or anesthetic care. Rechargeable SCS systems were not adversely affected when turned off for the duration of the pregnancy. CONCLUSION: Implantation of SCS devices in women of childbearing years should take into account the future needs of both obstetric and anesthetic care by avoiding the abdomen and lower lumbar spine whenever possible. There was no appreciable decline of battery capacity in present day constant current rechargeable generators when deactivated for the duration of pregnancy.

Continuous Glucose Monitoring, Glycemic Variability, and Excessive Fetal Growth in Pregnancies Complicated by Type 1 Diabetes.

BACKGROUND: To examine trimester-specific associations among glycemic variability, fetal growth, and birthweight in pregnancies with type 1 diabetes mellitus (Type 1 DM). METHODS: In this retrospective cohort study of 41 pregnant women with Type 1 DM, we used continuous glucose monitoring (CGM) data to calculate glycemic variability (coefficient of variation of glucose) over a 7-day interval in each trimester. Clinical data, including fetal biometry, birthweight, and perinatal complications, were extracted from medical records. RESULTS: Women maintained good glycemic control during pregnancy, with mean HbA1c in the first, second, and third trimester 6.5%, 6.1%, and 6.4%, respectively. Sixty-three percent of infants were large for gestational age (LGA). Estimated fetal weight percentile (EFW%ile) and abdominal circumference percentile (AC%ile) increased during pregnancy, consistent with accelerated prenatal growth. Correlations between trimester-specific glycemic variability and EFW, AC, and birthweight were not statistically significant. After maternal age adjustment, glycemic variability was not associated with birthweight for any trimester (adj. ß for first trimester: -38.46, 95% CI: -98.58 to 21.66; adj. ß for second trimester: -12.20, 95% CI: -51.47 to 27.06; adj. ß for third trimester: -26.26, 95% CI: -79.52 to 27.00). CONCLUSIONS: The occurrence of LGA remains very high in contemporary U.S. women with Type 1 DM, despite the use of CGM and overall good glycemic control. Neither HbA1c nor glycemic variability predicted fetal overgrowth or birthweight. Since LGA is a key driver of maternal and newborn complications in pregnancies with Type 1 DM, our data emphasize the importance of investigating both glucose-dependent and glucose-independent underlying mechanisms.

The association of circulating angiogenic factors and HbA1c with the risk of preeclampsia in women with preexisting diabetes.

OBJECTIVE: To assess whether glycemic control, soluble fms-like tyrosine kinase 1 (sFlt1) and placental growth factor (PlGF) were associated with the development of preeclampsia (PE) or gestational hypertension (GHTN) in women with preexisting diabetes. METHODS: Maternal circulating angiogenic factors (sFlt1 and PlGF) measured on automated platform were studied at four time points during pregnancy in women with diabetes (N = 159) and reported as multiples of the median (MOM) of sFlt1/PlGF ratio (median, 25th-75th percentile) noted in non-diabetic non-hypertensive control pregnant population (N = 139). Diagnosis of PE or GHTN was determined by review of de-identified clinical data. RESULTS: PE developed in 12% (N = 19) and GHTN developed in 23% (N = 37) of the women with diabetes. Among diabetic women without PE or GHTN, median sFlt1/PlGF levels at 35-40 weeks was threefold higher than in non-diabetic controls [MOM 3.21(1.19-7.24), p = 0.0001]. Diabetic women who subsequently developed PE had even greater alterations in sFlt1/PlGF ratio during the third trimester [MOM for PE at 27-34 weeks 15.18 (2.37-26.86), at 35-40 weeks 8.61(1.20-18.27), p ≤ 0.01 for both windows compared to non-diabetic controls]. Women with diabetes who subsequently developed GHTN also had significant alterations in angiogenic factors during third trimester; however, these findings were less striking. Among women with diabetes, glycosylated hemoglobin (HbA1c) during the first trimester was higher in subjects who subsequently developed PE (7.7 vs 6.7%, p = 0.0001 for diabetic PE vs diabetic non-PE). CONCLUSIONS: Women with diabetes had a markedly altered anti-angiogenic state late in pregnancy that was further exacerbated in subjects who developed PE. Altered angiogenic factors may be one mechanism for the increased risk of PE in this population. Increased HbA1c in the first trimester of pregnancies in women with diabetes was strongly associated with subsequent PE.

Effects of a low-glycemic load diet in overweight and obese pregnant women: a pilot randomized controlled trial.

BACKGROUND: The optimal diet for pregnancy that is complicated by excessive weight is unknown. OBJECTIVE: We aimed to examine the effects of a low-glycemic load (low-GL) diet in overweight and obese pregnant women. DESIGN: We randomly assigned 46 overweight or obese pregnant women to receive a low-GL or a low-fat diet. Participants received carbohydrate-rich foods, fats, and snack foods through home delivery or study visits. The primary outcome was birth weight z score. Other endpoints included infant anthropometric measurements, gestational duration, maternal weight gain, and maternal metabolic parameters. RESULTS: There were no significant differences in birth weight z score or other measures of infant adiposity between groups. However, in the low-GL compared with the low-fat group, gestational duration was longer (mean ± SD: 39.3 ± 1.1 compared with 37.9 ± 3.1 wk; P = 0.05) and fewer deliveries occurred at ≤ 38.0 wk (13% compared with 48%, P = 0.02; with exclusion of planned cesarean deliveries: 5% compared with 53%; P = 0.002). Adjusted head circumference was greater in the low-GL group (35.0 ± 0.8 compared with 34.2 ± 1.3 cm, P = 0.01). Women in the low-GL group had smaller increases in triglycerides [median (interquartile range): 49 (19, 70) compared with 93 (34, 129) mg/dL; P = 0.03] and total cholesterol [13 (0, 36) compared with 33 (22, 56) mg/dL, P = 0.04] and a greater decrease in C-reactive protein [-2.5 (-5.5, -0.7) compared with -0.4 (-1.4, 1.5) mg/dL, P = 0.007]. CONCLUSIONS: A low-GL diet resulted in longer pregnancy duration, greater infant head circumference, and improved maternal cardiovascular risk factors. Large-scale studies are warranted to evaluate whether dietary intervention during pregnancy aimed at lowering GL may be useful in the prevention of prematurity and other adverse maternal and infant outcomes. This trial is registered at clinicaltrials.gov as NCT00364403.

Risk of cesarean wound complications in diabetic gestations.

OBJECTIVE: This study was undertaken to examine the association between pregestational diabetes mellitus (DM) and wound complications after cesarean delivery (CD). STUDY DESIGN: This was a retrospective, observational cohort study in patients with type 1 and 2 DM compared with non-DM controls undergoing CD. Wound complications were defined as wound infection, wound separation greater than 1 cm, and wound dehiscence. RESULTS: There was an overall incidence of wound complications of 18.4% (34/185) in DM versus 5.8% (10/174) in non-DM (unadjusted odds ratio of 3.7; 95% CI = 1.8-7.7). Mean body mass index before pregnancy was 30.9 in DM versus 26.5 kg/m 2 in non-DM (P < .01). A multivariable logistic regression model adjusting for body mass index, length of surgery, and previous CD demonstrated a 2.5-fold increased risk of wound complications in DM patients compared with non-DM patients (95% CI = 1.1-5.5). CONCLUSION: Pregestational diabetes is associated with a 2.5-fold increase in wound complications after CD.