Effect of single embryo transfer on the risk of preterm birth associated with in vitro fertilization.

PURPOSE: To determine whether elective single embryo transfer (eSET) reduces the risk of preterm delivery associated with in vitro fertilization (IVF). METHODS: This is an observational study of 3125 eSET cycles performed from 2008 to 2009 and reported to the Society for Assisted Reproductive Technology (SART) database. Preterm delivery rates were compared to the overall preterm delivery rate among all patients undergoing IVF over the same time period. RESULTS: The 3125 eSET cycles resulted in 1507 live births (live birth rate 48.2 %) Among these deliveries were 27 twins (1.8 %) and one set of triplets (0.07 %). The overall preterm delivery rate (20-37 weeks gestation) following eSET was 17.6 % (269/1527). This is significantly greater than the preterm birth rate for all patients undergoing IVF over the same time period (12 %, P < 0.001). CONCLUSIONS: Elective single embryo transfer does not reduce the risk of preterm delivery associated with in vitro fertilization (IVF).

Vitamin D: metabolism.

The biologically active metabolite of vitamin D, 1,25(OH)(2)D(3), affects mineral homeostasis and has numerous other diverse physiologic functions including effects on growth of cancer cells and protection against certain immune disorders. This article reviews the role of vitamin D hydroxylases in providing a tightly regulated supply of 1,25(OH)(2)D(3). The role of extrarenal 1α(OH)ase in placenta and macrophages is also discussed, as well as regulation of vitamin D hydroxylases in aging and chronic kidney disease. Understanding specific factors involved in regulating the hydroxylases may lead to the design of drugs that can selectively modulate the hydroxylases. The ability to alter levels of these enzymes would have therapeutic potential for the treatment of various diseases, including bone loss disorders and certain immune diseases.

The state of the art of in vitro fertilization.

Since the first description of successful human in vitro fertilization in 1978, researchers and clinicians have been striving to improve the efficacy and safety of the technique. Advances in technology and in our understanding of human reproduction have contributed to increased success rates and decreased rates of higher order multiple births. However, there is still room for improvement as 'unexplained infertility' still affects many couples, and the incidence of twin pregnancies remains elevated. This review will discuss some of the recent advances in the fields of molecular genetics, proteomics and oocyte culture that will ultimately enhance the clinical practice of preimplantation genetic diagnosis, embryo selection and in vitro maturation. It will also discuss the potential for these advances to improve both the safety and efficacy of in vitro fertilization in the near future.

Vitamin D: metabolism.

The biologically active metabolite of vitamin D, 1,25(OH)(2)D(3), affects mineral homeostasis and has numerous other diverse physiologic functions including effects on growth of cancer cells and protection against certain immune disorders. This article reviews the role of vitamin D hydroxylases in providing a tightly regulated supply of 1,25(OH)(2)D(3). The role of extrarenal 1alpha(OH)ase in placenta and macrophages is also discussed, as well as regulation of vitamin D hydroxylases in aging and chronic kidney disease. Understanding specific factors involved in regulating the hydroxylases may lead to the design of drugs that can selectively modulate the hydroxylases. The ability to alter levels of these enzymes would have therapeutic potential for the treatment of various diseases, including bone loss disorders and certain immune diseases.

Evidence for a role of prolactin in calcium homeostasis: regulation of intestinal transient receptor potential vanilloid type 6, intestinal calcium absorption, and the 25-hydroxyvitamin D(3) 1alpha hydroxylase gene by prolactin.

Increased calcium transport has been observed in vitamin D-deficient pregnant and lactating rats, indicating that another factor besides 1,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) is involved in intestinal calcium transport. To investigate prolactin as a hormone involved in calcium homeostasis, vitamin D-deficient male mice were injected with 1,25(OH)(2)D(3), prolactin, or prolactin + 1,25(OH)(2)D(3). Prolactin alone (1 microg/g body weight 48, 24, and 4 h before termination) significantly induced duodenal transient receptor potential vanilloid type 6 (TRPV6) mRNA (4-fold) but caused no change in calbindin-D(9k). Combined treatment with 1,25(OH)(2)D(3) and prolactin resulted in an enhancement of the 1,25(OH)(2)D(3) induction of duodenal TRPV6 mRNA, calbindin-D(9k) mRNA, and an induction of duodenal calcium transport [P < 0.05 compared with 1,25(OH)(2)D(3) alone]. Because lactation is associated with an increase in circulating 1,25(OH)(2)D(3), experiments were done to determine whether prolactin also has a direct effect on induction of 25-hydroxyvitamin D(3) 1alpha hydroxylase [1alpha(OH)ase]. Using AOK B-50 cells cotransfected with the prolactin receptor and the mouse 1alpha(OH)ase promoter -1651/+22 cooperative effects between prolactin and signal transducer and activator of transcription 5 were observed in the regulation of 1alpha(OH)ase. In addition, in prolactin receptor transfected AOK B-50 cells, prolactin treatment (400 ng/ml) and signal transducer and activator of transcription 5 significantly induced 1alpha(OH)ase protein as determined by Western blot analysis. Thus, prolactin, by multiple mechanisms, including regulation of vitamin D metabolism, induction of TRPV6 mRNA, and cooperation with 1,25(OH)(2)D(3) in induction of intestinal calcium transport genes and intestinal calcium transport, can act as an important modulator of vitamin D-regulated calcium homeostasis.

Asymptomatic bacteriuria in pregestational diabetic pregnancies and the role of group B streptococcus.

We sought to determine if gravidas with pregestational diabetes mellitus (DM) are at increased risk for asymptomatic bacteriuria (ASB) compared with nondiabetic gravidas. This is a retrospective case-control study of 150 pregnant patients with pregestational DM and 294 nondiabetic controls. Rates of ASB and any colony count of group B streptococcus (GBS) bacteriuria were reviewed. The incidence of ASB among pregestational diabetics was higher compared with nondiabetic gravidas (18% versus 8.2%, odds ratio [OR] 2.47, 95% confidence interval [CI] 1.37 to 4.45). GBS was the most common organism in diabetic gravidas (26%). There was no difference in incidence of ASB recurrence (OR 1.26, 95% CI 0.37 to 4.36), but antibiotic resistance was higher in the control group (OR 0.28, 95% CI 0.09 to 0.91). Diabetic gravidas with ASB or any level of GBS bacteriuria had higher hemoglobin A (1c) values compared with diabetics without ASB (8.31 +/- 1.89 versus 7.31 +/- 1.84, P = 0.0035). Our results demonstrate that gravidas with DM are at increased risk of ASB including GBS bacteriuria compared with non-diabetic gravidas.

Robotic-assisted laparoscopic cerclage in a pregnant patient.

A robotic-assisted laparoscopic technique for transabdominal cerclage placement could offer improvements over the traditional laparoscopic approach. A gravid female with no vaginal portion of the cervix underwent a robotic-assisted laparoscopic cerclage at 12 weeks' gestation and ultimately delivered a healthy infant at term.