Prevalence of post-partum thyroiditis in Liguria (Italy): an observational study.
BACKGROUND
Post-partum thyroiditis (PPT) is an autoimmune disorder occurring within the first year following delivery. A variable prevalence has been reported in different surveys. We prospectively evaluated PPT prevalence and outcome in a cohort of pregnant women living in a well-defined geographic area.


OBJECTIVE
A subset from a group of healthy women consecutively evaluated for thyroid function and thyroid autoimmunity during pregnancy, referring to the same obstetric unit, were followed up at 4-6 months and 1 yr after delivery.


METHODS
Follow-up for PPT was performed in 258 pregnant women. Control data were obtained in a comparable group of healthy non-pregnant women. Free T3 (fT3), free T4 (fT4), TSH thyroglobulin/thyroid peroxidase autoantibodies (TgAb/TPOAb), and urinary iodine excretion were measured.


RESULTS
Autoantibody positivity was observed in 9.3% of pregnant, similar to control women. Forty-three out of 59 autoantibody-positive women were followed up; 23 showed PPT at the first control, 18 had hypothyroidism at 1 yr (5 had not shown PPT at the first control). Among 215 out of 584 autoantibody-negative women followed up, 27 developed PPT (15 of them without thyroid autoantibodies); 16 developed thyroid autoantibodies without PPT. After 1 yr, 9 women had hypothyroidism: only 1 of them was autoantibody-negative at the former control. Urinary iodine was increased in several pregnant women.


CONCLUSIONS
An overall PPT prevalence of about 18% may be estimated. PPT was also observed in autoantibody- negative women. Differences with other surveys may be related to both study protocol and characteristics of the population studied.
Filippi
U
U
Internal Medicine Unit, ASL3 Voltri Hospital, Genoa, Italy.
Brizzolara
R
R
Venuti
D
D
Cesarone
A
A
Maritati
V A
VA
Podestà
M
M
Yung
W F
WF
Bottaro
L C
LC
Orselli
A
A
Chiappori
A
A
Schiavo
M
M
Caputo
M
M
Bonassi
S
S
Bagnasco
M
M
D000328:Adult; D000465:Algorithms; D001323:Autoantibodies / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D018828:Immunoglobulins, Thyroid-Stimulating / Q000097:blood; D007453:Iodide Peroxidase / Q000276:immunology; D007455:Iodine / Q000652:urine; D007558:Italy / Q000453:epidemiology; D050032:Postpartum Thyroiditis / Q000097:blood / Q000453:epidemiology*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000097:blood / Q000652:urine; D015995:Prevalence; D013954:Thyroglobulin / Q000276:immunology; D055815:Young Adult
D001323:Autoantibodies; D018828:Immunoglobulins, Thyroid-Stimulating; D013954:Thyroglobulin; D007455:Iodine; D007453:Iodide Peroxidase