summary answer: Symptoms are mostly mild and 30% of women are asymptomatic. Surgical findings are mainly minimal; no visceral complications were found in this study. However, adhesions as well as pregnancies seem to be more common among women using Cu-IUDs. what is known already: Prior studies and case reports have suggested that uterine perforation by modern IUDs/IUSs is rarely serious. main results and the role of chance: The majority of patients (n ¼ 53; 71%) had mild symptoms of abnormal bleeding or abdominal pain or both, in combination with missing IUD/IUS threads. Asymptomatic patients (n ¼ 22; 29%) were examined because of missing threads or pregnancy. Failure to remove the IUD/IUS by pulling visible threads was the reason for referral in seven women (9%) requesting removal of the device. Eleven women (15%) were pregnant. Misplaced IUDs/IUSs were localized by a combination of vaginal ultrasonography (US) and X-ray, hysteroscopy or curettage. Only after this were patients treated by means of laparoscopy. The majority (n ¼ 44; 65%) of the 68 intra-abdominal devices were located in the omentum, the remaining 24 (35%) around the uterus. Partial perforation or myometrial embedding was diagnosed in all seven cases (9%) with visible threads, but unsuccessful removal by pulling. During laparoscopy, filmy adhesions were found in 21 patients (30%). Pregnancy (33 versus 7%, P ¼ 0.009) and intra-abdominal adhesions (58 versus 20%, P ¼ 0.002) were significantly more common in the Cu-IUD group. Infections were rare; one non-specific acute abdominal infection, later found to be unrelated to the IUD, led to laparoscopy and in four cases the IUD was surrounded by pus, but there were no symptoms of infection.limitations, reasons for caution: The study setting revealed only surgically treated symptomatic patients and asymptomatic women attending regular follow-up. Women not treated, but only followed or not attending follow-up, were not identified, excluding the possibility to analyse missed undiagnosed perforations, or conservative follow-up as a treatment option.wider implications of the findings: As surgical findings are minimal, asymptomatic women may need no treatment at all.An alternative form of contraception is, however, important as pregnancies do occur. If a woman plans a pregnancy, a misplaced LNG-IUS should be removed, as it may act as a contraceptive. study funding/competing interest(s): Helsinki University Central Hospital research funds. O.H. has lectured and designed educational events with Bayer AG and MSD, and serves occasionally on scientific advisory boards for these companies. S.S. has

As the study setting revealed only symptomatic patients or those attending regular follow-up, the true incidence might be somewhat higher. As there is no specific diagnostic code for uterine perforation or treatment, it is unlikely that all cases of uterine perforation can be identified in a retrospective study.

Decidual macrophages are in close contact with trophoblast cells during placenta development, and an appropriate crosstalk between these cellular compartments is crucial for the establishment and maintenance of a healthy pregnancy. During different phases of gestation, macrophages undergo dynamic changes to adjust to the different stages of fetal development. Trophoblast‐secreted factors are considered the main modulators responsible for macrophage differentiation and function. However, the phenotype of these macrophages induced by trophoblast‐secreted factors and the factors responsible for their polarization has not been elucidated. In this study, we characterized the phenotype and function of human trophoblast‐induced macrophages. Using in vitro models, we found that human trophoblast‐educated macrophages were CD14+CD206+CD86− and presented an unusual transcriptional profile in response to TLR4/LPS activation characterized by the expression of type I IFN‐β expression. IFN‐β further enhances the constitutive production of soluble programmed cell death ligand 1 (PD‐L1) from trophoblast cells. PD‐1 blockage inhibited trophoblast‐induced macrophage differentiation. Soluble PD‐L1 (sPD‐L1) was detected in the blood of pregnant women and increased throughout the gestation. Collectively, our data suggest the existence of a regulatory circuit at the maternal fetal interface wherein IFN‐β promotes sPD‐L1 expression/secretion by trophoblast cells, which can then initiate a PD‐L1/PD‐1‐mediated macrophage polarization toward an M2 phenotype, consequently decreasing inflammation. Macrophages then maintain the expression of sPD‐L1 by the trophoblasts through IFN‐β production induced through TLR4 ligation.