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Childbirth - Topic
Abstract
Parthenogenesis is the development of offspring from unfertilized eggs. Parthenogenesis forms a regular part of some sexual life cycles, but there are also many lineages of animals that have given up sexual reproduction and become obligately parthenogenetic. There are a number of genetically different types of parthenogenesis, ranging from gamete duplication, which immediately eliminates all heterozygosity, to apomixis and prezygotic doubling, which both preserve all the heterozygosity that was present in the mother. The existence of successful parthenogenetic lineages demonstrates that sex is not necessary for reproduction and raises the question of why sex exists. Parthenogenetic lineages are often successful in the short term but almost never persist in the evolutionary long term. An influential hypothesis holds that sexual populations persist longer than parthenogenetic populations because they evolve more rapidly in response to environmental challenges such as rapidly evolving parasites and pathogens. But the adaptive significance of sexual reproduction remains an open question, and parthenogenetic lineages play an important role in ongoing testing of this and other hypotheses.Hormonal Modulation
Birth control choice can be very important in patients with HS. Some patients describe gradually developing HS lesions after starting a new birth control: high-androgen containing OCPs and androgen-only birth control, even in the intrauterine device (IUD) form, can trigger and worsen HS.5 Clinicians should inquire of any potential contraindications to a type of birth control, such as having migraines with auras or long-term smoking. Additionally, birth control compliance should be discussed with patients to determine which birth control would be the best option for the patient.
Low-androgen OCPs, such as ethinyl estradiol-drospirenone and ethinyl estradiol-desogestrel, can benefit females who have perimenstrual flares with limited disease. This type of OCP can be used with spironolactone or by itself to prevent flares in this patient group.19 Copper-containing IUDs do not contain hormones and can also be a birth control option for patients.
Following discussion with patients about birth control, clinicians may determine whether changing birth control is recommended and also whether the patient plans on becoming pregnant in the near future. Patients may have an IUD or birth control implant that they prefer to remove at a later point. If this is the case, the clinician can provide the patient with a list of optimal birth control options once the patient chooses to change birth control.. The Birthing Bed
Birthing beds have gained increasing popularity and use in the United States. These beds combine the advantages of the birthing chair (mobility, ease of position change, decreased pain in second stage, improved bearing down) with the advantages of a traditional delivery table (at least for the birth attendant), while being much more comfortable than either the chair or the table. Although expensive to purchase, they are increasingly incorporated into birthing units in hospital and nonhospital settings. These multiposition beds allow a delivering patient to assume a variety of positions and facilitate upright positioning. They have the advantage of equal usability for nontraditional and traditional or operative deliveries.6.11 Myositis
Seasonal birth patterns were identified in subgroups of patients with myositis, suggesting an etiologic role of early environmental exposures. Some subgroups of patients with juvenile myositis had seasonal birth distributions. Patients with juvenile dermatomyositis with the p155 autoantibody had a birth distribution that differed significantly from that of patients with p155 antibody-negative juvenile dermatomyositis. Patients with juvenile myositis with the HLA risk factor allele DRB1*0301 and patients with myositis with the linked allele DQA1*0501 had a birth distribution significantly different from those without the alleles. Birth distributions seem to have greater seasonality in juvenile than in adult myositis subgroups, suggesting greater influence of perinatal exposures in childhood-onset illness.91