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Hyperemesis gravidarum (HG) is a condition causing severe nausea and vomiting in early pregnancy often resulting in hospital admission. The incidence of HG is approximately 0.5% of live births, said to be higher in multiple pregnancies, hydatidiform mole and other conditions associated with increased pregnancy hormone levels. Both the aetiology and pathogenesis of HG remain unknown. We conducted a literature review (1966-now) to summarize the current evidence on the aetiology and pathogenesis of HG. The potential role of pregnancy-related hormones such as progesterone, estrogen and HCG has been widely studied; however, various other hormones such as leptin, placental growth hormone, prolactin, thyroid and adrenal cortical hormones have been implicated in the aetiology of HG. In addition to endocrinological hypotheses, the rationale and evidence considering infectious, immunological, psychological, metabolic and anatomical causes for HG have been analysed here. Many studies suffer from the low number of patients included, the variable definition used for HG and varying assay methodology used in studies of hormone measurement. This review highlights the need for more extensive studies addressing the pathogenesis and aetiology of HG.

Preimplantation genetic diagnosis (PGD) of single gene defects following assisted conception typically involves removal of single cells from preimplantation embryos and analysis using highly sensitive PCR amplification methods taking stringent precautions to prevent contamination from foreign or previously amplified DNA. Recently, whole genome amplification has been achieved from small quantities of genomic DNA by isothermal amplification with bacteriophage 29 DNA polymerase- and exonuclease-resistant random hexamer primers. Here we report that isothermal whole genome amplification from single and small numbers of lymphocytes and blastomeres isolated from cleavage stage embryos yielded microgram quantities of amplified DNA, and allowed analysis of 20 different loci, including the DeltaF508 deletion causing cystic fibrosis and polymorphic repeat sequences used in DNA fingerprinting. As with analysis by PCR-based methods, some preferential amplification or allele drop-out at heterozygous loci was detected with single cells. With 2-5 cells, amplification was more consistent and with 10 or 20 cells results were indistinguishable from genomic DNA. The use of isothermal whole genome amplification as a universal first step marks a new era for PGD since, unlike previous PCR-based methods, sufficient DNA is amplified for diagnosis of any known single gene defect by standard methods and conditions.

No abstract

A total of 110 consecutive women was studied prospectively at the time of transcervical embryo transfer following conventional in-vitro fertilization and intracytoplasmic sperm injection procedures. Microbiological cultures were performed on endocervical swabs and embryo transfer catheter tips. Positive microbial growths were observed from endocervical swabs in 78 (70.9%) women and from catheter tips in 54 (49.1%) women. The clinical pregnancy rates were 57.1% in the group of patients without growth and 29.6% in the group with positive microbial growth from catheter tips. As microbial contamination at embryo transfer may influence implantation rates, prospective studies are justified to determine whether eradication of endocervical micro-organisms is possible and whether their eradication will improve implantation rates.