Phillip G. Stubblefield

Non-invasive optical monitoring of the newborn piglet brain using continuous-wave and frequency-domain spectroscopy

We have used continuous-wave (CW) and frequency-domain spectroscopy to investigate the optical properties of the newborn piglet brain in vivo and non-invasively. Three anaesthetized, intubated, ventilated and instrumented newborn piglets were placed into a stereotaxic instrument for optimal experimental stability, reproducible probe-to-scalp optical contact and 3D adjustment of the optical probe. By measuring the absolute values of the brain absorption and reduced scattering coefficients at two wavelengths (758 and 830 nm), frequency-domain spectroscopy provided absolute readings (in contrast to the relative readings of CW spectroscopy) of cerebral haemoglobin concentration and saturation during experimentally induced perturbations in cerebral haemodynamics and oxygenation. Such perturbations included a modulation of the inspired oxygen concentration, transient brain asphyxia, carotid artery occlusion and terminal brain asphyxia. The baseline cerebral haemoglobin saturation and concentration, measured with frequency-domain spectroscopy, were about 60% and 42 microM respectively. The cerebral saturation values ranged from a minimum of 17% (during transient brain asphyxia) to a maximum of 80% (during recovery from transient brain asphyxia). To analyse the CW optical data, we have (a) derived a mathematical relationship between the cerebral optical properties and the differential pathlength factor and (b) introduced a method based on the spatial dependence of the detected intensity (dc slope method). The analysis of the cerebral optical signals associated with the arterial pulse and with respiration demonstrates that motion artefacts can significantly affect the intensity recorded from a single optode pair. Motion artefacts can be strongly reduced by combining data from multiple optodes to provide relative readings in the dc slope method. We also report significant biphasic changes (initial decrease and successive increase) in the reduced scattering coefficient measured in the brain after the piglet had been sacrificed.

No association between coffee consumption and adverse outcomes of pregnancy.

We analyzed interview and medical-record data of 12,205 non-diabetic, non-asthmatic women to evaluate the relation between coffee consumption and adverse outcomes of pregnancy. Low birth weight and short gestation occurred more often among offspring of women who drank four or more cups of coffee a day and more often among the offspring of smokers. After controlling for smoking, other habits, demographic characteristics, and medical history by standardization and logistic regression, we found no relation between low birth weight or short gestation and heavy coffee consumption. Furthermore, there was no excess of malformations among coffee drinkers. These negative results suggest that coffee consumption has a minimal effect, if any, on the outcome of pregnancy.

The association of alcohol consumption with outcome of pregnancy

Patterns of alcohol consumption were assessed in 12,440 pregnant women interviewed at the time of delivery. Only 92 women (0.7 per cent) reported drinking 14 or more drinks per week, with most consuming fewer than 21 drinks per week. In the crude data, alcohol intake of 14 or more drinks per week was associated with a variety of adverse pregnancy outcomes, including low birthweight, gestational age under 37 weeks, stillbirth, and placenta abruptio. After use of logistic regression to control for confounding by demographic characteristics, smoking, parity and obstetric history, only the association of placenta abruptio with alcohol consumption of 14 or more drinks per week remained statistically significant. With the exception of placenta abruptio, alcohol intake of fewer than 14 drinks per week was not associated with and increased risk of any adverse outcome. No association was seen with congenital malformations at any level of alcohol intake.

Low-dose oral contraceptives and bone mineral density: an evidence-based analysis

We reviewed studies of the association of oral contraceptive (OC) use and bone mineral density (BMD). We limited the review to studies of women using low-dose oral contraceptives and that measured BMD by bone densitometry. A total of 13 studies met the inclusion criteria. Nine of these showed a positive effect of OC use on BMD, and four did not show an association. However, none of the studies showed a decrease in BMD with OC use. We classified the level of evidence from each study according to the guidelines of the US Preventive Services Task Force. The level of evidence supporting a positive association between OC use and increased BMD is II-1. There is fair evidence (Category B) to support the position that OC use has a favorable effect on BMD. We made suggestions for a study design that could yield Level I evidence.

Management of Unintended and Abnormal Pregnancy: Comprehensive Abortion Care

This book was written as an authoritative update to the previous textbook produced in 1999 by the National Abortion Federation (NAF). The previous text, A Clinician’s Guide to Medical and Surgical Abortion, addressed rapidly changing issues of the time in the provision of excellent abortion care. This new text further updates the ongoing evolution of the field, in an area of medical care with a fairly scanty literature. The important context of such work is the immense political and religious turmoil in the United States, and the world, on the subject of abortion, despite the fact that it is one of the most common procedures performed in medicine. Abortion has been a common, if often hidden, fact of life in all cultures, in all periods of history. Unsafe abortion leads, all too often, to death or permanent injury; safe abortion is much medically safer than continuing a pregnancy. The intent of this book is to improve the provision of safe abortion. The book addresses a broad range of abortion-related issues, from the sociopolitical and global health challenges, to technical aspects of specialized areas of abortion care such as late pregnancy terminations and selective reduction of multiple gestations, as well as practical aspects of counseling, contraception, and requirements for establishing safe services. There is a comprehensive appendix of resources for abortion providers. The book is consistently readable. The organization is sound, and the progression of chapters and topics flows quite smoothly. What I particularly appreciated was the flexibility of recommendations. Many clinicians will have strong preferences for the “right” way to do things. This text strives to offer appropriate options for individual practice, without insisting on a specific method. The panel of editors includes some of the most highly regarded experts in the field and draws on a distinguished group of authors, including some from England, Sweden, and the World Health Organization in Switzerland. I was disappointed by the absence of family physicians in the authorial collection. Family physicians are an increasingly active group within the abortion community, and increasing access to abortion training in family medicine residencies is an area of ongoing activism within our field. Physicians from several disciplines other than OB-GYN, particularly family medicine and pediatrics, have produced significant research in the abortion field and have contributed considerably to the provision of abortion services, particularly in communities where there would otherwise be little to no access to such care. This book will be most useful for clinicians providing abortion care, at every level of training and experience, from medical students to senior practitioners. It will, however, also prove useful for those interested in the social, psychological, and public health aspects of abortion. Many readers will learn from a single reading; abortion clinicians will want this book on their reference shelf.

Work and Pregnancy

Pregnancy outcomes of 7,155 women who worked between one and nine months of pregnancy were compared with outcomes of 4,018 women who were not employed. There were no differences in rates of prematurity, Apgar score, birthweight, perinatal death rate, or malformation prevalence. Working women were divided into those who left employment during the first eight months and those who worked all nine months. The latter had a lower rate of adverse outcome than the other working group and the nonworking group. This indicates that working to term in the absence of contraindications does not impose an added risk on mother or infant. After control of confounding by parity and other relevant factors, an increased risk of prolonged gestational age was seen among primiparous working women. There was an increased risk of fetal distress among those women leaving work prior to nine months who were having their third or subsequent child. A small decrease in birth weight was seen among women who left work prior to term but not among those who worked all nine months. Overall the results are reassuring that working during pregnancy is not in itself a risk factor for adverse outcome.

Ectopic pregnancy and prior induced abortion.

We compared the prior pregnancy histories of 85 multigravid women with an ectopic pregnancy and 498 multigravid delivery comparison subjects. We found a relationship between the number of prior induced abortions and the risk of ectopic pregnancy: the crude relative risk of ectopic pregnancy was 1.6 for women with one prior induced abortion and 4.0 for women with two or more prior induced abortions; however, use of multivariate techniques to control confounding factors reduced the relative risks to 1.3 (95 per cent confidence interval, 0.6-2.7) and 2.6 (95 per cent confidence interval, 0.9-7.4), respectively. The analysis suggests that induced abortion may be one of several risk factors for ectopic pregnancy, particularly for women who have had abortions plus pelvic inflammatory disease or multiple abortions.

Methods for induced abortion

We describe present methods for induced abortion used in the United States. The most common procedure is first-trimester vacuum curettage. Analgesia is usually provided with a paracervical block and is not completely effective. Pretreatment with nonsteroidal analgesics and conscious sedation augment analgesia but only to a modest extent. Cervical dilation is accomplished with conventional tapered dilators, hygroscopic dilators, or misoprostol. Manual vacuum curettage is as safe and effective as the electric uterine aspirator for procedures through 10 weeks of gestation. Common complications and their management are presented. Early abortion with mifepristone/misoprostol combinations is replacing some surgical abortions. Two mifepristone/misoprostol regimens are used. The rare serious complications of medical abortion are described. Twelve percent of abortions are performed in the second trimester, the majority of these by dilation and evacuation (D&E) after laminaria dilation of the cervix. Uterine evacuation is accomplished with heavy ovum forceps augmented by 14-16 mm vacuum cannula systems. Cervical injection of dilute vasopressin reduces blood loss. Operative ultrasonography is reported to reduce perforation risk of D&E. Dilation and evacuation procedures have evolved to include intact D&E and combination methods for more advanced gestations. Vaginal misoprostol is as effective as dinoprostone for second-trimester labor-induction abortion and appears to be replacing older methods. Mifepristone/misoprostol combinations appear more effective than misoprostol alone. Uterine rupture has been reported in women with uterine scars with misoprostol abortion in the second trimester. Fetal intracardiac injection to reduce multiple pregnancies or selectively abort an anomalous twin is accepted therapy. Outcomes for the remaining pregnancy have improved with experience.

Pain of first-trimester abortion: its quantification and relations with other variables.

Among 2,299 patients on whom first-trimester abortions were performed after administration of local anesthesia, 97 per cent reported experiencing some degree of pain. Independent ratings of the pain severity were obtained from the patients and also from the doctors and counselors who observed them. Although the rating procedures used by patients from those used by doctors and counselors, the three sources agreed significantly in evaluating pain levels of individual patients. Data from all three sources indicated that pain produced during the abortion procedure tended to be minor in severity. The ranking of relative painfulness of the eight stages of the aborton procedure based on average ratings obtained from doctors was nearly identical to that based on average ratings obtained from counselors. (Patients did not rate the separate stages.) On average, the patients rated the pain as being less than earache or toothache, but more than headache or bachache. The youngest patients experienced the most pain, and the oldest experienced the least. Both gestational age and cervical dilatation were related to pain in a curvilinear fashion, i.e., for both variables, patients in extreme categories experienced more pain than those in intermediate categories. Preprocedure fearfulness was positively related to intraoperative pain. No support was found for the expectation that oral administration of 5 mg. of diazepam reduces pain during this procedure.

Neonatal hypoglycemia after beta-sympathomimetic tocolytic therapy

The effect of oral beta-sympathomimetic tocolytic therapy on neonatal serum glucose concentrations in the first several hours after delivery was examined in 12 babies. Hypoglycemia was noted in eight babies, and was sustained over at least a 30-minute period in five. The group with sustained hypoglycemia had a higher cord serum insulin concentration, a lower serum glucose nadir, and a more rapid initial rate of serum glucose disappearance than those babies with normoglycemia or transient hypoglycemia. Sustained hypoglycemia was observed in five of six babies delivered within two days of the termination of tocolytic therapy, but was not present in any of six babies delivered five or more days after the end of tocolytic therapy. Speculations as to the interaction between beta-sympathomimetic tocolytic drugs administered to the mother and fetal and neonatal glucose metabolism are made.