{
    "abstract": "Thyroid axis dysregulation during controlled ovarian hyperstimulation (COH) is more pronounced in hypothyroid-treated women. Whether or not this leads to compromised thyroid hormone levels within the ovarian follicular fluid is not known.\nTo determine whether ovarian follicular thyroid hormone levels are compromised in adequately replaced hypothyroid women undergoing controlled ovarian hyperstimulation (COH), and/or influence cycle/pregnancy outcomes.\nProspective cohort study involving 46 euthyroid (anti-thyroid peroxidase antibody negative) and 16 levothyroxine-replaced women with baseline thyroid-stimulating hormone (TSH) <2.5 mIU/L attending their first COH cycle. Follicular fluid TSH, free triiodothyronine (T3) and free thyroxine (T4) were recorded at oocyte pick-up. Serum levels were measured at: (i) baseline; (ii) human chorionic gonadotropin trigger day; and (iii) cycle conclusion. The number of mature oocytes retrieved, fertilisation, early pregnancy loss and live birth rates were compared.\nMedian serum TSH levels were similar at baseline (1.76 vs 1.24 mIU/L, P\u2009=\u20090.053), but free T3 levels were lower (4.5 vs 4.8\u2009pmol/L, P\u2009=\u20090.029) in levothyroxine-replaced compared to euthyroid women, with serum TSH levels increasing across ovarian stimulation (P\u2009=\u20090.006) into pregnancy testing (P\u2009=\u20090.030). Follicular fluid free T3 levels were lower in levothyroxine-replaced women (median 4.3 vs 4.6\u2009pmol/L, P\u2009=\u20090.032). Fertilisation rates were lower (52% vs 71%, P\u2009=\u20090.043) in women requiring levothyroxine replacement, but numbers of mature oocytes retrieved, early pregnancy loss and live births did not differ.\nAdequately replaced hypothyroid women achieve lower ovarian follicular fluid free T3 levels and poorer fertilisation rates compared to euthyroid women undergoing COH. Optimising T3 levels may be pivotal in improving COH outcomes in hypothyroid women.",
    "authors": [
        {
            "affiliation": "Westmead Fertility Centre, Westmead Hospital, Sydney, New South Wales, Australia.\nDepartment of Diabetes and Endocrinology, Westmead Hospital, Sydney, New South Wales, Australia.",
            "firstname": "Rachel A",
            "initials": "RA",
            "lastname": "Bradbury"
        },
        {
            "affiliation": "Western Sydney Local Health District (WSLHD) Research and Education Network, Westmead Hospital, Sydney, New South Wales, Australia.\nNational Health and Medical Research Council (NHMRC) Clinical Trial Centre, University of Sydney, Sydney, New South Wales, Australia.",
            "firstname": "Karen",
            "initials": "K",
            "lastname": "Byth"
        },
        {
            "affiliation": "Westmead Fertility Centre, Westmead Hospital, Sydney, New South Wales, Australia.\nDepartment of Diabetes and Endocrinology, Westmead Hospital, Sydney, New South Wales, Australia.",
            "firstname": "Howard C",
            "initials": "HC",
            "lastname": "Smith"
        }
    ],
    "conclusions": "Adequately replaced hypothyroid women achieve lower ovarian follicular fluid free T3 levels and poorer fertilisation rates compared to euthyroid women undergoing COH. Optimising T3 levels may be pivotal in improving COH outcomes in hypothyroid women.",
    "copyrights": "\u00a9 2024 Royal Australian and New Zealand College of Obstetricians and Gynaecologists.",
    "doi": "10.1111/ajo.13854",
    "journal": "The Australian & New Zealand journal of obstetrics & gynaecology",
    "keywords": [
        "assisted reproduction",
        "controlled ovarian hyperstimulation",
        "hypothyroid",
        "levothyroxine",
        "thyroid hormone"
    ],
    "methods": null,
    "publication_date": "2024-06-26",
    "pubmed_id": "38922816",
    "results": "Median serum TSH levels were similar at baseline (1.76 vs 1.24 mIU/L, P\u2009=\u20090.053), but free T3 levels were lower (4.5 vs 4.8\u2009pmol/L, P\u2009=\u20090.029) in levothyroxine-replaced compared to euthyroid women, with serum TSH levels increasing across ovarian stimulation (P\u2009=\u20090.006) into pregnancy testing (P\u2009=\u20090.030). Follicular fluid free T3 levels were lower in levothyroxine-replaced women (median 4.3 vs 4.6\u2009pmol/L, P\u2009=\u20090.032). Fertilisation rates were lower (52% vs 71%, P\u2009=\u20090.043) in women requiring levothyroxine replacement, but numbers of mature oocytes retrieved, early pregnancy loss and live births did not differ.",
    "title": "Levothyroxine may not adequately prepare hypothyroid women for controlled ovarian hyperstimulation.",
    "xml": "<Element 'PubmedArticle' at 0x78850312ba60>"
}