Levothyroxine Increases Delivery Rate among Women with Subclinical Hypothyroidism Seeking Assisted Reproductive Technology

DynaMed Weekly Update - Volume 5, Issue 20

Subclinical hypothyroidism has been reported in as many as 40% of women with infertility, though prevalence estimates vary widely. A recent randomized trial evaluated the effects of levothyroxine treatment on pregnancy outcomes in 70 women seeking assisted reproductive technology (ART) who had subclinical hypothyroidism. At the time of screening, participants had thyroid stimulating hormone (TSH) > 4 microunits/mL. The women were randomized to levothyroxine 50-100 mcg orally once daily vs. placebo beginning one month prior to starting ART. All participants were treated with a long agonist ovarian stimulation protocol and had intracytoplasmic sperm injection. Women who became pregnant continued their randomized treatment throughout pregnancy. The levothyroxine group had a significantly higher delivery rate than the placebo group (26% vs. 3%, NNT 5) (level 1 [likely reliable] evidence). Levothyroxine also increased the rate of clinical pregnancy (35% vs. 10%, p < 0.05, NNT 4) and decreased the rate of miscarriage (9% vs. 13%, p < 0.05, NNT 25). Patients in the treatment group achieved normalized TSH while the placebo group continued to have elevated TSH (mean TSH levels 1.1 microunits/L vs. 4.9 microunits/L, p < 0.05) (Endocr Pract. 2010 Mar 29:1).

For more information, see the Infertility and Hypothyroidism topics in DynaMed.


HPV DNA-based Testing Associated with Reduced Invasive Cervical Cancer Compared to Cytology

The addition of HPV DNA testing to either conventional or liquid-based cytology has previously been shown to increase detection rates of high-grade cervical intraepithelial neoplasia (CIN). A new randomized trial provides evidence that HPV DNA-based testing may reduce the rate of invasive cervical cancer compared to cytology (level 2 [mid-level] evidence). A total of 94,370 women aged 25-60 years were randomized in two phases to HPV testing plus liquid-based cytology vs. conventional cytology (phase 1), or HPV testing alone vs. conventional cytology (phase 2). In both phases, all women with abnormal cytology were referred for colposcopy. In addition, in phase 1, if cytology was normal, women aged 35-60 years with positive HPV test were referred for colposcopy, but women aged 25-34 years were referred to colposcopy only if HPV testing was positive on repeated testing (or if cytology became abnormal). In phase 2, all women with a positive HPV test were referred for colposcopy. A second round of cytology-only screening within 3-5 years was performed in 73% of the cytology groups and 72% of the DNA testing groups. The 2 phases were pooled for analysis.

Similar rates of invasive cervical cancer were detected in both groups during the initial round of screening. Invasive cervical cancer was detected in 7 women in the DNA testing groups and 9 women in the cytology-only groups. However, the DNA testing group had a significantly lower rate of invasive cancer detected during the second round of screening (0 vs. 0.027% [9 cases], p = 0.004, number needed to screen [NNS] 3,700). The invasive cancer rate was also lower in for DNA testing in a subgroup analysis of women aged 35-60 years (p = 0.016, NNS 4,800), but not in younger women.

The strength of the conclusions is limited by the pooling of the data from the 2 phases, which had different protocols. It is therefore unclear whether the results apply to HPV DNA testing alone, the combination of HPV DNA testing and cytology, or both (Lancet Oncol 2010 Mar;11(3):249).

For more information, see the Human papillomavirus DNA testing topic in DynaMed.