Thesis (M.S.)--University of Michigan, 1993.

Thesis (M.S.)--University of Michigan, 1993.

Despite the fact that many Nigerian women have limited access to pharmacologic methods for pain management during labor,1,2 previous studies have indicated a demand for such options.3–5 Opioids are a frequently offered analgesic method,5,6 but there are associated risks to the fetus with this type of pain management.7 The use of epidurals, another common method of labor analgesia, has not become prevalent in Nigeria due to lack of awareness, lack of resources, expense, and women’s beliefs that it is not necessary and/or it is harmful.3 Nitrous oxide is an alternative labor analgesic that has reduced side effects compared to opioids and offers pain reduction without the loss of body movement and positioning as is seen with epidurals.7 Because Nigerian women have expressed an interest in increased options for labor analgesics, and nitrous oxide aligns with some of their cultural desires,8 offering nitrous oxide could increase maternal satisfaction.9–12 The literature review examines epidurals, opioids, and nitrous oxide for use as labor analgesics, including their mechanisms of action, benefits, and side effects. It also reviews Nigerian cultural beliefs, the advantages and disadvantages of using nitrous oxide in Nigeria, current practice in Nigeria regarding labor analgesia, Nigerian women’s and healthcare providers opinions on analgesia, additional maternal advantages of labor analgesia outside of pain relief, and birthing locations in Nigeria. The study will be an exploratory, descriptive cross-sectional study that will use a questionnaire to obtain data regarding pregnant women’s knowledge of, and attitudes toward, nitrous oxide as an analgesic during childbirth. It will be administered to 270 pregnant women who visit an antenatal clinic at the Primary Health Care facilities in Mushin Local Government Area located in the state of Lagos, Nigeria. Descriptive statistics of the participants will be reported, and the chi-squared test will be used to determine the associations between the demographics and awareness of various analgesic options, cultural acceptability of using nitrous oxide for labor pain management, and the desirability to use nitrous oxide as a labor analgesic. The use of nitrous oxide for labor analgesia could provide Nigerian women with an important option apart from only opioids or epidurals. It could decrease the use of opioids, thus decreasing their associated health risks during labor.3 Additionally, because vaginal deliveries are an important cultural desire of Nigerian women, nitrous oxide could provide a method for pain management during labor that does not lead to increased risk of cesarean section.13,14

Labor may perhaps be the most painful a woman might experience, although characterized by large inter-individual variability. The perceived pain during labor is the result of diverse factors, i.e. her previous pain experiences, the analgesia she receives and maybe also her genes. The overall aim of this thesis was to investigate biological and psychological mechanisms underlying inter-individual differences in labor pain related behaviors. The mechanisms that characterize endogenous pain relief during labor are not fully understood, though it is known to be partly explained by the effects of β-endorphin (BE). BE plasma levels were followed longitudinally in a cohort of pregnant women and were found to remain unchanged between early and late pregnancy, although with a nadir in the beginning of the third trimester. Furthermore, women with low levels of BE in plasma at the end of the third trimester, required second line labor analgesia to a significantly higher extent than women with normal levels. In a population-based sample of 814 pregnant women we investigated if inter-individual differences in labor pain related behavior was influenced by the pain-protective single nucleotide polymorphism (SNP) combination of guanosine triphosphate cyclohydrolase (GCH1) and the opioid receptor µ-1 gene (OPRM1) A118G SNP. We identified a possible association between the pain-protective SNP combination of GCH1 and use of second line analgesia. No association was found between the OPRM1 and use of analgesia or labor pain related behavior. The association between self-rated antenatal depressed mood and anxiety in relation to pain behaviors and self-reported pain during labor was investigated. We found that depressed mood during pregnancy is associated with early arrival to the delivery department, whereas antenatal anxiety is associated with increased self-rated pain prior to labor analgesia.  In conclusion, although an increasing number of studies strongly suggest that genetic predisposition plays an important role in pain and pain-related mechanisms, GCH1 and OPRM1 has little to offer in terms of individual counseling on labor analgesia. To enable the future use of genetic variability for pre-labor testing and counseling, a number of different genes reflecting pain mediation pathways, involving biological and psychological mechanisms, need to be analyzed in combination.