Abstract
BACKGROUND:
Spina bifida is the most common fetal anomaly of the central nervous system, which affects approximately 1:1000 live births in the United States. Myelomeningocele (MMC) is the most common presentation of spina bifida, representing half of these cases. Given the deformation to the spinal cord and the nerve roots, this defect may result in significant morbidity to infants and major life-long disabilities. In this study we aimed to identify maternal and fetal characteristics associated with expectant management or termination of pregnancy in the setting of antenatally diagnosed MMC. We hypothesized that the level of the defect would correlate with patient’s decision to continue the pregnancy.
METHODS:
A retrospective cohort analysis was performed with patients who had presented to the Cleveland Clinic Fetal Care Center between 2005–2017.
RESULTS:
Our data showed 36% of patients with antenatal diagnosis of MMC elected for second trimester terminations versus 64% who chose to continue their pregnancy and deliver either by cesarean section or vaginal delivery. Based on ultrasound findings, there were no significant differences between these two groups. Maternal body mass index was significantly higher in those who continued pregnancies (p = 0.036). In addition, the fetal diagnostic methods chosen by patients were significantly different. Those who elected to terminate were more likely to pursue amniocentesis (p = 0.03) and less likely to opt for MRI characterization of the fetus (p = 0.007).
CONCLUSION:
We conclude, in the setting of fetal MMC diagnosed during pregnancy, patients often rely less on the associated ultrasonographic findings. Personal decisions likely influence the choice of other fetal diagnostic modalities. Other than BMI, we did not see an association between maternal factors and decisions regarding second trimester pregnancy termination.
Introduction
Spina bifida is the most common fetal anomaly of the central nervous system, which affects 0.5–1 in 1000 live births in the United States. MMC is the most common presentation of spina bifida, representing half of these cases [1]. MMC is characterized by a spinal column defect allowing for the extrusion of the spinal cord through this defect within a meningeal membrane. Given the deformation to the spinal cord and the nerve roots, this defect can result in significant morbidity to infants and major life-long disabilities.
The severity of the myelopathic dysfunctions (motor and sensory deficits, bowel and bladder dysfunction) correlate with the respective level of extrusion of the spinal cord. In addition to these spinal cord deficits, infants born with MMC concurrently present with Arnold-Chiari II malformation, characterized by hydrocephalus, brain stem anomalies and ventricular displacement [2]. Hydrocephalus is treated surgically by ventricular-peritoneal (VP) shunting. Complications of VP shunting include infection and shunt failure [3].
The first human in-utero repair of a MMC was performed in 1997. Published in 2013, the management of MMC study (MOMS) compared prenatal (in utero) vs postnatal repair of this fetal anomaly [4]. This trial was closed early after 158 patients were randomized (183 eligible and consented) due to dramatic differences in results. Antenatal repair of MMC resulted in a decreased need for shunt placement and in fewer patients with brain herniation. Complications of antenatal repair included pre-term delivery, abruption and pulmonary edema. Fetal surgery is further limited by access and patient acceptability.
In the present study, we identified a number of patients who were receiving care in or referred to the Cleveland Clinic Fetal Care Center with an antenatal diagnosis of fetal MMC. These patients were then followed by neurology, urology, maternal fetal medicine and neonatology within our system for characteristics of pregnancy and pregnancy outcomes. We sought to identify a number of patient characteristics in those continuing or not continuing the pregnancy when faced with this fetal central nervous system abnormality. We hypothesized that the level of the defect would correlate with patient’s decision to continue the pregnancy.
Materials and methods
Institutional review board approval was obtained from the Cleveland Clinic Foundation prior to obtaining cohort information. Maternal demographic, prenatal and ultrasound information was obtained retrospectively from electronic medical records within our institution from 2005–2017. Inclusion criteria included maternal age between 18 and 39 and viable pregnancy and the detection of fetal neural tube defect between 14 weeks 37 weeks of gestation in obstetric ultrasonography. Exclusion criteria were the following: Multi-fetal gestations, fetal death, suspected fatal congenital anomalies or chromosomal abnormalities. All patients who met criteria were offered fetal surgery and declined except one as noted. At our center, all patients are counseled on termination of pregnancy and the state limit is 21.6 weeks gestational age, otherwise patients are referred to other institutions for later gestational age terminations. Data was collected and stored using a REDCap (Research Electronic Data Capture) electronic data capture tools hosted at the Cleveland Clinic. REDCap is a secure, web-based application designed to support data capture for research studies (https://redcap.vanderbilt.edu).
Statistical analysis
Categorical factors were summarized using frequencies and percentages, while continuous measures summaries used means +/- SD or median and range as appropriate. Pearson chi-square and Fisher’s exact tests Kruskal-Wallis were used. Analysis was performed using SAS software (version 9.4; Cary, NC).
Results
After review of electronic medical records, complete information was available for 45 patients who presented to the Fetal Care Center with an antenatal diagnosis of fetal MMC between 2005 and 2017. The average gestational age at diagnosis was 20.3 weeks. Among these, 29 (64.4%) decided to pursue expectant management versus 16 (35.6%) who decided to proceed with second trimester termination of pregnancy. Among maternal characteristics and demographics, a greater BMI (32.0 vs 23.9 p = 0.036) among women continuing expectant management was noted.
With respect to antenatal testing, we noted significant differences in the approaches sought by patients with relation to their desire to continue or not terminate pregnancy. Patients who desired to continue pregnancy were more likely (82.8% versus 43.8% p < 0.007) (Table 1) to undergo further fetal imaging including fetal MRI. Patients planning on termination of pregnancy were more likely to pursue invasive fetal testing in the form of amniocentesis (75.0% vs 41.4%, p = 0.03) (Table 1).
Maternal and pregnancy characteristics
Maternal and pregnancy characteristics
Maternal and pregnancy outcomes. Review of records reveals differences in maternal characteristics and association with patient’s decisions. BMI: body mass index. MRI: magnetic resonance imaging. IUGR: intrauterine growth restriction. Values presented as Mean ± SD, Median [P25, P75], Median (min, max) or N (column %). p-values: a = ANOVA, b = Kruskal-Wallis test, c = Pearson’s chi-square test, d = Fisher’s Exact test.
Complete ultrasonographic information was available for all 45 patients (Table 2). No differences, other than vertex presentation were noted in the ultrasound findings between the two groups, though presentation is variable at this gestational age. Of note, only one chromosomal abnormality was noted in our cohort. There was no difference in other ultrasound characteristics in those continuing or not continuing pregnancy.
Ultrasonographic characteristic. Second trimester ultrasound findings uncovered no significant differences in the 2 groups
Values presented as Mean±SD, Median [P25, P75], Median (min, max) or N (column %). p-values: a = ANOVA, b = Kruskal-Wallis test, c = Pearson’s chi-square test, d = Fisher’s Exact test.
Despite recent advances in fetal surgery, MMC remains a difficult antenatal diagnosis for many patients to process. In fact, while patients should be offered fetal interventions, the overall maternal and fetal morbidity of surgery should be taken into consideration. Here we present both demographic and ultrasonographic characteristics of pregnancies in which patients elected continued expectant management or termination of pregnancy. In our cohort, patients with greater BMIs were more likely to continue expectant management of pregnancy, most of which subsequently resulted in cesarean section. It is difficult to theorize why many women make the decisions they do. There is a chance they were counseled against termination due to concerns about procedural complications [5]. It is important to note that 91% (20/22) of these patients subsequently underwent primary low transverse cesarean section for delivery, which is also complicated by greater BMIs [6]. The mode of delivery in this case appeared to be driven by obstetrician or neurosurgeon preference. These would be supported by small studies, which recommend scheduled cesarean delivery prior to the onset of labor in the setting of term pregnancy complicated by MMC [7]. However, more recent data suggest no difference between modes of delivery and infant neurologic outcomes [8].
Strength of our study is the large number of patients evaluated. There are few studies trying to evaluate pregnancy characteristics that might affect patient decision-making. Most patients were from within our large academic hospital system; however, some referred from outside our system. A limitation of our study is that there is a possibility some patients may have decided to terminate their pregnancy prior referral to our center.
An advantage of antenatal MMC diagnosis by ultrasonography is the ability to pursue further counseling, imaging, and genetic testing prior to legal decisions to continue pregnancy or terminate. Elective termination of pregnancy is limited to 21.6 weeks gestational age in Ohio. While patients presented to our center up to 37 weeks, the diagnosis had been made earlier in pregnancy (mid-second trimester) and patients were referred for delivery planning. In our cohort, women who decided to pursue expectant management had further imaging in the form of fetal MRI. Conversely, amniocentesis was most commonly performed in patients who underwent dilation & evacuation (D&E) for pregnancy termination. Given infant deficits (neurogenic bladder, bowel incontinence, paraplegia, etc.) may be associated with the level of the MMC [9], further imaging may provide patients with infant expectations with respect to quality of life.
Optimal antenatal management of MMC remains an area of uncertainty. Direct comparisons of cases in which patients pursued expectant management versus termination of pregnancy revealed differences in further diagnostic testing.
Conclusion
Unexpectedly, we uncovered the precise ultrasonographic findings did not seem to have an effect on patients decisions. Taken together, our presented data allows for better patient counseling when faced with this difficult antenatal diagnosis.
Author disclosures
The authors report no disclosures or conflicts of interest.
Financial disclosures
No financial sources were used for this project.