Short answer

Under Missouri law, a valid prenuptial (premarital) agreement can limit or waive a spouse’s rights in the other spouse’s property and estate, including rights that would otherwise arise by will or intestacy. A prenup can therefore affect life estate arrangements or the size of what you would otherwise inherit, provided the agreement is enforceable. If an executor refuses to provide the agreement or information about the estate, beneficiaries and interested persons generally have several remedies through the probate court, including demanding an accounting or petitioning the court to compel disclosure or remove the executor for breach of fiduciary duty.

Detailed answer — how a prenuptial agreement can affect estate shares in Missouri

1. What a prenuptial agreement can do

A prenuptial agreement is a contract between two people made before marriage that typically addresses ownership and distribution of property if the marriage ends by divorce or death. In Missouri, parties may use a premarital agreement to:

• identify property as separate or marital;
• waive or limit spousal rights to a share of the other spouse’s estate (including rights that might be claimed by will or by intestacy);
• specify whether a surviving spouse will take a life estate in property or waive that right;
• set out how retirement accounts, business interests, or other assets will be treated on death.

In short, if a prenup says that the surviving spouse gives up a right to a life estate or to a statutory share, courts generally will enforce that waiver if the agreement was validly made and remains enforceable at the time of death.

2. How life estates are affected

A life estate is a right to use property for the life of the life tenant (often the surviving spouse). A life estate can be created in a will, in a deed, or by operation of law. A valid premarital agreement that specifically addresses rights at death (for example, saying the spouse waives any future life estate or certain testamentary rights) can prevent a later-created life estate from giving the surviving spouse additional rights that contradict the agreement. Conversely, if the prenup preserves or creates a life estate for the surviving spouse, that provision will govern even if a later will tries to change it—subject to the usual rules about estate administration and property law.

3. When a prenuptial agreement is enforceable

To be enforced, a premarital agreement typically must meet basic contract requirements: it must be in writing and signed by both parties. Courts will consider whether the agreement was entered into voluntarily, whether there was adequate disclosure of assets (or an informed waiver of such disclosure), and whether enforcement would be unconscionable under the circumstances. If a party can show fraud, duress, lack of capacity, or that the agreement was unconscionable when executed (or later circumstances make enforcement unconscionable), a court may refuse to enforce it.

4. How a prenup interacts with wills and deeds

A will cannot normally override a valid premarital agreement. If the prenup waives a spouse’s probate claims, then a later will that attempts to give the spouse more than the prenup allows will generally not be able to override the waiver. Similarly, if a deed or other instrument purports to create a life estate inconsistent with the parties’ premarital agreement, the instrument may be limited by the agreement depending on timing and notice.

5. Practical impact on your share

If your mother signed a valid premarital agreement that limits her spouse’s rights, that can increase what she can leave to you (because the spouse’s claims will be smaller). Conversely, if the prenup gives the spouse rights or designates property as belonging to the spouse, you may receive less. The exact effect depends on the prenup’s wording, whether the spouse has waived statutory rights, whether any life estate was reserved, and whether the agreement is ultimately enforceable in court.

What to do if the executor refuses to provide the prenuptial agreement or estate information

1. Understand the executor’s duties

The executor (personal representative) has fiduciary duties to beneficiaries and interested persons. Those duties generally include managing assets prudently, providing information about the estate, filing required inventories and accountings with the probate court, and following the will and governing law. Beneficiaries and other interested persons ordinarily have the right to request reasonable information about the estate and to receive court-ordered accountings.

2. Practical steps you can take

1. Ask for the document in writing. Make a clear written request to the executor (or the executor’s attorney) asking for a copy of the prenuptial agreement and stating your interest in the estate. Keep a dated copy of the request.
2. Review public probate filings. Check the probate court where your mother’s estate is administered. Many filings (petitions, inventories, accountings) are public records. The court file may already include an inventory or list of assets that helps you understand estate property and whether a prenup was referenced.
3. Request an accounting. If the executor refuses to cooperate, you may file a petition in probate court asking the court to compel an accounting and production of documents. Courts can order discovery or require the executor to provide estate records.
4. Move to compel production or for sanctions. If the executor will not comply with a court order, you can ask the court to compel production of documents, impose sanctions, or in serious cases remove the executor for breach of fiduciary duty.
5. Get counsel. An estate or probate attorney experienced in Missouri law can send formal demand letters, file the necessary petitions with the probate court, and represent your interests efficiently.

3. Typical court remedies

The probate court may:

• order production of the prenuptial agreement and other estate records;
• require the executor to file detailed accountings;
• award costs and attorney fees if the executor’s refusal was improper;
• remove or suspend the executor for breach of duty;
• resolve disputes about the enforceability of the prenup so the court can distribute assets according to law and valid agreements.

Sources and where to look in Missouri

Missouri’s statutes and court rules cover premarital agreements and probate procedure. You can review Missouri law and probate court resources at these official sites:

• Missouri Revised Statutes and searchable code: https://revisor.mo.gov/
• Missouri Courts — official court information and links to local probate courts: https://www.courts.mo.gov/
• Uniform Premarital (Prenuptial) Agreement Act — text and background (useful for comparison with state law): https://www.uniformlaws.org/acts/premaritalagreements

If you want to find specific statutory provisions cited by Missouri courts, start at the Missouri Revisor site and search terms such as “premarital agreement,” “probate,” “personal representative,” “accounting,” and “life estate.”

When to talk to an attorney

Talk with a Missouri probate or estate attorney if:

• you suspect a prenup affects your inheritance and you don’t have a copy;
• the executor refuses to provide required documents or information;
• you believe the executor is mismanaging estate assets or breaching fiduciary duties;
• you need to challenge the validity or enforceability of a prenup.

An attorney can assess whether the agreement appears enforceable, draft and file court petitions, and represent you at hearings.

Helpful Hints

• Make written requests and keep copies. A dated letter or email creates a record of your attempt to obtain information.
• Check the probate file early. Many estate matters are documented in the court file; you may find inventories, petitions, and sometimes copies of material agreements.
• Be precise in requests. Ask specifically for the prenuptial agreement, any marital property agreements, deeds that create life estates, and the executor’s inventories and accountings.
• Act quickly. Probate deadlines and statutory time limits can be short; prompt action preserves your rights.
• Consider mediation. Some disputes over disclosures or contested provisions can be resolved quicker and cheaper by mediation than by litigation.
• Ask about fee-shifting. In some cases courts may award attorney fees against a fiduciary who refuses to comply with disclosure obligations.