Study to analyze electronic medical records of women using an intrauterine device (IUD). The study was required by the FDA for the marketed IUD Mirena (US Post-marketing requirement; short name of study: APEX IUD). The study analyzed the risks that the IUD was expelled or perforated the womb for the following group comparisons: * Women who were breastfeeding at the time of IUD insertion and within 52 weeks postpartum versus women who were not breastfeeding at the time of IUD insertion and within 52 weeks postpartum. * Women who had a first observed IUD insertion within different time periods after childbirth (i.e., ≤ 6 weeks, \> 6 weeks and ≤ 14 weeks, \> 14 weeks and ≤ 52 weeks) versus women who had their first observed IUD insertion more than 52 weeks after childbirth, including women without a recorded delivery within the past 52 weeks. An additional analysis involved 5-level postpartum timing (i.e., 0 to 3 days, 4 days to ≤ 6 weeks, \> 6 weeks to ≤ 14 weeks, \> 14 weeks to ≤ 52 weeks) versus the \> 52 week postpartum group. The study also analyzed the risks that the IUD was expelled or perforated the womb for different types of IUDs. In addition, the study aimed to assess the following interactions: * The extent to which the type of IUD (IUDs releasing the hormone LNG versus Copper IUDs) modified the risk that an IUD was expelled or perforated the womb in relation to breastfeeding and/ or in relation to the point in time when the IUD was inserted after childbirth. * The extent to which the breastfeeding status modified the risk that an IUD was expelled or perforated the womb in relation to the point in time when the IUD was inserted after childbirth.
Study Type
OBSERVATIONAL
Enrollment
326,658
Intrauterine devices, e.g. BAY86-5028 (Mirena, Skyla, Kyleena), Liletta and ParaGard
Kaiser Permanente Northern California
Oakland, California, United States
Kaiser Permanente Southern California
Pasadena, California, United States
Regenstrief Institute
Indianapolis, Indiana, United States
Kaiser Permanente Washington
Seattle, Washington, United States
Crude Incidence Rate of Uterine Perforation Stratified by Breastfeeding Status Among Women Within 52 Weeks Postpartum-first Observed IUD Insertions
Crude incidence rate was calculated as the number of outcomes occurring during the person-time at risk divided by the total person-time at risk (in person-years)
Time frame: Up to 11 years
Cumulative Incidence of Uterine Perforation Stratified by Breastfeeding Status Among Women Within 52 Weeks Postpartum-first Observed IUD Insertions
Crude estimates of the cumulative incidence, defined as number of outcomes occurring up to a time point out of the number of IUD insertions
Time frame: At 1 year and 5 years of follow-up
Adjusted Hazard Ratio (HR) for Breastfeeding Status and Uterine Perforation-first Observed IUD Insertions
Propensity score-adjusted hazard ratio to evaluate whether the risk of uterine perforation among women who were breastfeeding at the time of first observed IUD insertion differs from the risk of uterine perforation among women who were not breastfeeding at the time of first observed IUD insertion
Time frame: Up to 11 years
Crude Incidence Rate of Uterine Perforation Categorized by Postpartum Timing-first Observed IUD Insertions
Crude incidence rate was calculated as the number of outcomes occurring during the person-time at risk divided by the total person-time at risk (in person-years)
Time frame: Up to 11 years
Cumulative Incidence of Uterine Perforation Categorized by Postpartum Timing-first Observed IUD Insertions
Crude estimates of the cumulative incidence, defined as number of outcomes occurring up to a time point out of the number of IUD insertions
Time frame: At 1 year and 5 years of follow-up
Adjusted Hazard Ratio (HR) for Postpartum Timing and Uterine Perforation-first Observed IUD Insertions
Adjusted for propensity scores and breastfeeding status, to evaluate whether the risk of uterine perforation among women who had a first observed IUD insertion within different time periods postpartum differs from the risk of uterine perforation among women who had their first observed IUD insertion more than 52 weeks postpartum, including women without a recorded delivery within the past 52 weeks. Reference group: IUD insertion \> 52 weeks postpartum
Time frame: Up to 11 years
Adjusted Hazard Ratio (HR) for Postpartum Timing Risk 14-week Cut Point and Uterine Perforation-first Observed IUD Insertions
Adjusted for propensity scores and breastfeeding status, to estimate the risk of uterine perforation among women who had a first observed IUD insertion early in the postpartum period (i.e., up to 14 weeks postpartum) versus those who had a first observed IUD insertion late in the postpartum period (i.e., more than 14 weeks postpartum, including women without recorded delivery within the past 52 weeks). Reference group: IUD insertion \>14 weeks postpartum or with no recorded delivery
Time frame: Up to 11 years
Adjusted Hazard Ratio (HR) for Postpartum Timing Risk 36-week Cut Point and Uterine Perforation-first Observed IUD Insertions
Adjusted for propensity scores and breastfeeding status, to estimate the risk of uterine perforation among women who had a first observed IUD insertion ≤ 36 weeks postpartum versus women who had a first observed IUD insertion \> 36 weeks postpartum, including women without recorded delivery within the past 52 weeks. Reference group: IUD insertion \>36 weeks postpartum or with no recorded delivery
Time frame: Up to 11 years
Adjusted Incidence Rate Ratio (IRR) for Uterine Perforation-first Observed IUD Insertions
Adjusted for propensity score, overall and stratified by breastfeeding status at the time of IUD insertion for ≤ 36 weeks postpartum at IUD insertion versus \> 36 weeks postpartum or with no recorded delivery, at 1 year and 5 years of follow-up. Reference group: \> 36 weeks or no delivery
Time frame: At 1 year and 5 years of follow-up
Adjusted Incidence Rate Difference (IRD) for Uterine Perforation-first Observed IUD Insertions
Propensity score-adjusted incidence rate differences (per 1,000 person-years) for uterine perforation for women ≤ 36 weeks postpartum at IUD insertion compared with those who were \> 36 weeks postpartum or with no recorded delivery, 1 year of follow-up and 5 years of follow-up, overall and stratified by breastfeeding status. Reference group: \> 36 weeks or no delivery
Time frame: At 1 year and 5 years of follow-up
Crude Incidence Rate of Uterine Perforation Stratified by IUD Type-first Observed IUD Insertions
Crude incidence rate was calculated as the number of outcomes occurring during the person-time at risk divided by the total person-time at risk (in person-years)
Time frame: Up to 11 years
Cumulative Incidence of Uterine Perforation Stratified by IUD Type-first Observed IUD Insertions
Crude estimates of the cumulative incidence, defined as number of outcomes occurring up to a time point out of the number of IUD insertions
Time frame: At 1 year and 5 years of follow-up
Adjusted Hazard Ratio (HR) for IUD Type and Uterine Perforation-first Observed IUD Insertions
Propensity score-adjusted hazard ratio to evaluate whether the risk of uterine perforation among women with LNG-releasing IUD at the time of first observed IUD insertion differs from the risk of uterine perforation among women with copper IUD at the time of first observed IUD insertion
Time frame: Up to 11 years
Crude Incidence Rate of Uterine Perforation Stratified by Menorrhagia Status-first Observed IUD Insertions
Crude incidence rate was calculated as the number of outcomes occurring during the person-time at risk divided by the total person-time at risk (in person-years)
Time frame: Up to 11 years
Cumulative Incidence of Uterine Perforation Stratified by Menorrhagia Status-first Observed IUD Insertions
Crude estimates of the cumulative incidence, defined as number of outcomes occurring up to a time point out of the number of IUD insertions
Time frame: At 1 year and 5 years of follow-up
Adjusted Hazard Ratio (HR) for Menorrhagia Status and Uterine Perforation-first Observed IUD Insertions
Propensity score-adjusted hazard ratio to evaluate whether the risk of uterine perforation among women using an IUD who have at least one diagnosis code indicating menorrhagia in the 12 months before IUD insertion differs from the risk of uterine perforation among women who do not have this indication
Time frame: Up to 11 years
Effect Modification of Breastfeeding Status on Postpartum Timing for Uterine Perforation
Propensity score-adjusted hazard ratios to evaluate the extent to which breastfeeding status (yes vs. no) modified the association of uterine perforation for women with IUD insertion at different time periods postpartum (i.e., IUD insertion ≤ 14 weeks versus IUD insertion \> 14 weeks postpartum) among women with a recorded delivery within the past 52 weeks at the time of the first observed IUD insertion
Time frame: Up to 11 years
Effect Modification of IUD Type on Breastfeeding Status for Uterine Perforation
Propensity score-adjusted hazard ratios to evaluate the extent to which type of IUD (LNG-IUD vs. copper IUD) modified the association between uterine perforation and breastfeeding among women who were and were not breastfeeding at the time of first observed IUD insertion
Time frame: Up to 11 years
Effect Modification of IUD Type on Postpartum Timing for Uterine Perforation
Adjusted for propensity score and breastfeeding status, to evaluate the extent to which type of IUD (LNG-IUD vs. copper IUD) modified the association between uterine perforation and postpartum timing of IUD insertion for women with IUD insertion at different time periods postpartum (i.e., ≤ 6 weeks, \> 6 and ≤ 14 weeks, \> 14 and ≤ 52 weeks) versus IUD insertion more than 52 weeks postpartum, including no recorded delivery within the past 52 weeks, at the time of the first observed IUD insertion. Reference group: LNG-IUD or Copper IUD, \> 52 weeks or no delivery
Time frame: Up to 11 years
Crude Incidence Rate of IUD Expulsion Stratified by Breastfeeding Status Among Women Within 52 Weeks Postpartum-first Observed IUD Insertions
Crude incidence rate was calculated as the number of outcomes occurring during the person-time at risk divided by the total person-time at risk (in person-years)
Time frame: Up to 11 years
Cumulative Incidence of IUD Expulsion Stratified by Breastfeeding Status Among Women Within 52 Weeks Postpartum-first Observed IUD Insertions
Crude estimates of the cumulative incidence, defined as number of outcomes occurring up to a time point out of the number of IUD insertions
Time frame: At 1 year and 5 years of follow-up
Adjusted Hazard Ratio (HR) for Breastfeeding Status and IUD Expulsion-first Observed IUD Insertions
Propensity score-adjusted to evaluate whether the risk of IUD expulsion among women who were breastfeeding at the time of first observed IUD insertion differs from the risk of IUD expulsion among women who were not breastfeeding at the time of first observed IUD insertion
Time frame: Up to 11 years
Crude Incidence Rate of IUD Expulsion Categorized by Postpartum Timing-first Observed IUD Insertions
Crude incidence rate was calculated as the number of outcomes occurring during the person-time at risk divided by the total person-time at risk (in person-years)
Time frame: Up to 11 years
Cumulative Incidence of IUD Expulsion Categorized by Postpartum Timing-first Observed IUD Insertions
Crude estimates of the cumulative incidence, defined as number of outcomes occurring up to a time point out of the number of IUD insertions
Time frame: At 1 year and 5 years of follow-up
Adjusted Hazard Ratio (HR) for Postpartum Timing and IUD Expulsion-first Observed IUD Insertions
Adjusted for propensity score and breastfeeding status, to evaluate whether the risk of IUD expulsion before and after 49 days of insertion among women who had a first observed IUD insertion within different time periods postpartum differs from the risk of IUD expulsion among women who had their first observed IUD insertion more than 52 weeks postpartum, including women without a recorded delivery within the past 52 weeks Reference group: IUD insertion \> 52 weeks postpartum
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Time frame: Up to 11 years
Adjusted Hazard Ratio (HR) for Postpartum Timing Risk 14-week Cut Point and IUD Expulsion-first Observed IUD Insertions
Adjusted for propensity scores, to estimate the risk of IUD expulsion among women who had a first observed IUD insertion early in the postpartum period (i.e., up to 14 weeks postpartum) versus those who had a first observed IUD insertion late in the postpartum period (i.e., more than 14 weeks postpartum, including women without recorded delivery within the past 52 weeks). Reference group: IUD insertion \>14 weeks postpartum or with no recorded delivery
Time frame: Up to 11 years
Adjusted Hazard Ratio (HR) for Postpartum Timing Risk 36-week Cut Point and IUD Expulsion-first Observed IUD Insertions
Adjusted for propensity scores, to estimate the risk of IUD expulsion among women who had a first observed IUD insertion ≤ 36 weeks postpartum versus women who had a first observed IUD insertion \> 36 weeks postpartum, including women without recorded delivery within the past 52 weeks. Reference group: IUD insertion \>36 weeks postpartum or with no recorded delivery
Time frame: Up to 11 years
Adjusted Incidence Rate Ratio (IRR) for IUD Expulsion-first Observed IUD Insertions
Overall and stratified by breastfeeding status at the time of IUD insertion for IUD expulsion for ≤ 36 weeks postpartum at IUD insertion versus \> 36 weeks postpartum or with no recorded delivery, at 1 year and 5 years of follow-up Reference group: \> 36 weeks or no delivery
Time frame: At 1 year and 5 years of follow-up
Adjusted Incidence Rate Difference (IRD) for IUD Expulsion-first Observed IUD Insertions
Adjusted incidence rate differences (per 1,000 person-years) for IUD expulsion for women ≤ 36 weeks postpartum at IUD insertion compared with those who were \> 36 weeks postpartum or with no recorded delivery, 1 year of follow-up and 5 years of follow-up, overall and stratified by breastfeeding status Reference group: \> 36 weeks or no delivery
Time frame: At 1 year and 5 years of follow-up
Crude Incidence Rate of IUD Expulsion Stratified by IUD Type-first Observed IUD Insertions
Crude incidence rate was calculated as the number of outcomes occurring during the person-time at risk divided by the total person-time at risk (in person-years)
Time frame: Up to 11 years
Cumulative Incidence of IUD Expulsion Stratified by IUD Type-first Observed IUD Insertions
Crude estimates of the cumulative incidence, defined as number of outcomes occurring up to a time point out of the number of IUD insertions
Time frame: At 1 year and 5 years of follow-up
Adjusted Hazard Ratio (HR) for IUD Type and IUD Expulsion-first Observed IUD Insertions
Propensity score adjusted to evaluate whether the risk of IUD expulsion among women with LNG-releasing IUD at the time of first observed IUD insertion differs from the risk of IUD expulsion among women with copper IUD at the time of first observed IUD insertion
Time frame: Up to 11 years
Crude Incidence Rate of IUD Expulsion Stratified by Menorrhagia Status-first Observed IUD Insertions
Crude incidence rate was calculated as the number of outcomes occurring during the person-time at risk divided by the total person-time at risk (in person-years)
Time frame: Up to 11 years
Cumulative Incidence of IUD Expulsion Stratified by Menorrhagia Status-first Observed IUD Insertions
Crude estimates of the cumulative incidence, defined as number of outcomes occurring up to a time point out of the number of IUD insertions
Time frame: At 1 year and 5 years of follow-up
Adjusted Hazard Ratio (HR) for Menorrhagia Status and IUD Expulsion-first Observed IUD Insertions
Propensity score adjusted to evaluate whether the risk of IUD expulsion among women using an IUD who have at least one diagnosis code indicating menorrhagia in the 12 months before IUD insertion differs from the risk of IUD expulsion among women who do not have this indication
Time frame: Up to 11 years
Effect Modification of IUD Type on Breastfeeding Status for IUD Expulsion
Propensity score-adjusted hazard ratios to evaluate the extent to which type of IUD (LNG-IUD vs. copper IUD) modified the association between IUD expulsion and breastfeeding among women who were and were not breastfeeding at the time of first observed IUD insertion
Time frame: Up to 11 years
Effect Modification of IUD Type on Postpartum Timing for IUD Expulsion
Adjusted for propensity score and breastfeeding status, to evaluate the extent to which type of IUD (LNG-IUD vs. copper IUD) modified the association between IUD expulsion and postpartum timing of IUD insertion for women with IUD insertion at different time periods postpartum (i.e., ≤ 6 weeks, \> 6 and ≤ 14 weeks, \> 14 and ≤ 52 weeks) versus IUD insertion more than 52 weeks postpartum, including no recorded delivery within the past 52 weeks, at the time of the first observed IUD insertion. Reference group: LNG-IUD or Copper IUD, \> 52 weeks or no delivery
Time frame: Up to 11 years
Number of Indicators of a Potentially Difficult Insertion, Overall, by Breastfeeding Status, and by Postpartum Timing of IUD Insertion-first Observed IUD Insertions
To describe the prevalence of indicators of a difficult IUD insertion (e.g., need for cervical dilation, ultrasound guidance, paracervical block, clinician not indicating difficulty, use of misoprostol among all users)
Time frame: Up to 11 years
Number of Indicators of a Potentially Difficult Insertion, Overall, by IUD Type and by Menorrhagia Status-first Observed IUD Insertions
To describe the prevalence of indicators of a difficult IUD insertion (e.g., need for cervical dilation, ultrasound guidance, paracervical block, clinician not indicating difficulty, use of misoprostol among all users)
Time frame: Up to 11 years